I recently found out about a company called Dorco which sells razors online. They are equivalent in quality and features to the Gillette blades that cost 4 per cartridge at the grocery store, but theirs are more like .70 per cartridge. I ordered a year’s supply for about $45, and now I don’t have to bug grocery store employees to unlock the razor case to buy blades at prices that feel like extortion.
It never would have occurred to me to look online for something like razor blades. Anyone have other suggestions for mundane things that are far cheaper or more convenient to get online that others might not have thought to look for? Maybe services too…
I won’t link to specific sites because it depends too much on where you live, but ordering dry pet food in bulk online can be very, very good value for money. The one I got, found via Ebay but sold by a farm, is much better nutritionally than supermarket-bought dry pet food (I got cat and dog food and I looked up what makes dry pet food nutritional - percentages of meat, etc - then compared them to what was on offer) and so, so much cheaper - like a 20th of the cost, possibly more.
What is shipping like for pet food, especially in bulk? I have dogs and cats, so I’d be interested in links. I suppose it would be worth looking into litter as well.
I can’t remember the postage - it was a very small sum, and I’m in the UK, so my links wouldn’t help you. Amazon actually sometimes have good links for this stuff as well as ebay.
I did benefit by them accidentally sending ten times what I ordered and then saying they didn’t want the rest back (it would have cost too much to send someone down to collect it for my one purchase - they presumably combined their orders when sending it) but even so, there were a lot of other similar suppliers. Dry pet food is an easy thing to store in bulk and a total arse to transport yourself. I get my cat litter online too.
I also have a daughter with an unusual name who has friends with unusual names, so they never find bracelets or whatever with their names on. After a fun day at a bead shop, I looked at beaded letters (for home-made jewellery) online and ordered 1000 assorted letters for 9p on Amazon. That’s not a typo. So I now have 10,000 assorted letters at home. 
Things that are either very small, like your razors, or very bulky, like pet food, are best bought online. Guitar plectrums, for example - guitarists lose them all the time and they’re tenths of pennies per piece online. Replacement rings for piercings are very good value online too.
There are no razors at that web site. Did you mean this one?