Manufacturers like their employees to use their product. One car manufacturer I know not only allows employees a good discount (through a dealer) but forces anyone with a rival’s car to park in the far-away part of the car park. A biscuit maker allows employees to buy the broken and misshaped biscuits for a nominal price, but they are limited to one bag at a time.
When You Work For A Manufacturer, Do You Still Have To Go Through Retail Channels To Buy Its Product
I had a brief project at a Johnson & Johnson factory. They had a company store on the premises that all the employees frequented.
My uncle used to be a truck driver for Brach’s Candy. His garage was full of boxes of candy that quite literally “fell off the truck.” But I’m pretty sure that wasn’t a sanctioned process.
Worked for Dell and Apple distributor (small country, so only second and third tier distribution applied) and in both cases you could get whatever on bulk price in reasonable quantities (like 1 pc a year). But margins were awful. 10% tops. Probably even worse now.
Not directly related to working for the manufacturer and I don’t know if they still do it, but Intel Retailedge would offer really big discounts on some of their their products (usually top of the line) once or twice a year. You had be employed at an approved retail or online store (the list is really long) and review and answer training questions for several months online. And you had to be employed at the time you made the purchase. The more questions you answered, the bigger the discount. Back in the mid-2000’s, I got a top of the line processor and a midline mainboard for less than half the retail price of the processor alone.
Microsoft also had/has a program for IT people who would get free Windows and Office products for attending their launch seminars. I’m not talking about being beta testers. When I worked at OfficeMax, my co-worker who was the Technology supervisor, got me invited to the 2007 MS Office launch. After about a two hour seminar, we walked out with a bag of goodies which included a full retail version of MS 2007 Office Pro.
I worked for Dell from 2009-12 and we were allowed four coupons per year (one per quarter) allowing the user (we were allowed to give the coupons to others) to purchase whatever computer or accessory they wanted at the discounted employee price, which was 17% off full list. I heard from others who knew people working for Microsoft that the software products could be bought for very little and even some of the hardware products, but not the XBox game systems. They didn’t offer an employee discount on those.
BTW, the OP gives the example of someone in a Miracle Whip plant who wants to take a bottle home to refill the larder. I imagine (not having worked in a food manufacturing plant) that you couldn’t just take a bottle off the line without resulting in an inventory shortage. But as suggested, perhaps there were bottles that were set aside because the labels were askew and those could be purchased or taken by employees?
Again, not a manufacturer (sorry of the slightly OT) a large (the largest) food distributor here has an onsite (of the warehouse/office) retail store that sells overstock or damaged (as in the case or one bottle of a case broke) items at a steep discount. I would think wherever you are has someplace similar.
I’ve heard stories that the loaders and unloaders of the delivery trucks are often closely monitored to prevent them from “accidentally” dropping a a case of Miracle Whip so they could buy it at discount later. There…brought it kind of back to the OP’s question. 
I worked for a small to medium manufacturer of industrial products, but some could be used in your home. We had to set up the employee as a dealer in order to sell them products. It was a pain.
I’m an IT professional and I’ve received free stuff many times over the years. Microsoft once invited me and a supervisor to a seminar where they were talking about Windows 7 and Server 2008 R2 (Win7 wasn’t officially out to the public yet). We got free breakfast and they also handed us a goodie bag that included a high end wireless mouse and a full version of Win7 (which, again, you couldn’t yet buy in stores). The seminar itself was free. Companies want us to use and like their products so that we’ll turn around and recommend it to our company.
Now I work for the government. Nobody offers me anything anymore and I couldn’t accept gifts if they did. Oh well.
I once worked for Alcon, back when they were owned by Nestle. There was a company store that sold many of the products produced by the various companies under the Nestle umbrella. The prices were somewhat better than you’d see at retail, but not anything amazing.
Some car companies also have supplier discounts. I worked for a tier one supplier to the big three and many others. GM and Ford both have supplier purchase rates, you get a certificate from GM (or Ford) and take it to the dealer. You order the car(or pick one from the lot) and the cert gives you a fixed, discounted price (no haggling) which is about 20% or so off MSRP. Sometimes a great deal, sometimes less so. I used the discount twice in 22 years. You could use it every year. You had to keep the car for a year.
To those who know someone or bought a car directly from/through the manufacturer was the discount really large, say >$1000? From what I hear, there’s some really tricky behind the scenes accounting done with cars, manufacturer rebates/discounts, salespeople incentives, etc. that ensure a dealership never loses money on a deal. I hear a lot about “employee pricing” at car dealership sales, but take it with a huge grain of salt.
I had a friend who knew the sales manager of car dealership who gave me a good deal, several thousand off their sticker on the car, but when my friend bought a more expensive car from him a few months later, she said she couldn’t say how much she paid, but it was heavily inferred that it was close to what I paid.
Thank Toledo Jim. You answered my first question while I was composing.
And sometimes those codes or discount codes meant for a particular buyer goes public and fun ensues!
A friend of my dad’s owned a company that made plastic meat trays. His policy was that employees were allowed to take home a case every quarter. That was more meat trays than anyone would want to use, but not so many that it was worth selling them. (It turns out that when you get plastic meat trays for free, you find a lot of uses for them. My dad got a bunch from his friend, and put one under every potted plant, used them as drip trays to defrost messy things, etc.
I also know a guy who works for a beer distributor that gives away beer to the employees.
I think the idea of the meat tray owner was that he wanted employees to distinguish clearly between taking home a reasonable number of trays and actually stealing from the company, and he wanted all the basically-honest employees to have no temptation at all to steal more than he gave them, so they wouldn’t be sympathetic to the ones who actually wanted to steal product and sell it on the side.
I worked in Beer, and I could buy a reasonable amount for personal use (a couple of bottles a day) , only through salary deduction: they didn’t have a cash office.
Plus enough for a couple of drinks every day, wholesale, discounted, and tax paid (because they’d closed the free bar).
At my present location, I can get items at wholesale. It’s not the kind of item you’d buy more than once or twice in a lifetime.
You cannot buy a car directly from the manufacturer. Not even if you work for the manufacturer.
I have done a fair amount of work for a major brewery over the years. Their employees get two cases of beer free every month.
On the rare occasions that I go to one of the brewery sites, they usually give me a free case of beer, too.
I like working for breweries. 
I worked for Hostess bakery for a while. IIRC, we were allowed to take items from the line at a point after packaging but before boxing. You could eat all you wanted, but couldn’t leave the bakery with anything. This only applied to individually packaged stuff, I couldn’t take a loaf of bread.
I originally thought it was madness to allow employees unlimited Twinkies, but soon found out you’ll tire of anything after a constant diet.
I worked for a company that manufactured office paper. They had to purchase their office paper from a retailer to use in their own offices.