I took my car (2005 Mazda 3 hatchback) to Tire Discounters because the car shook at highway speeds. I thought it might need an alignment. It didn’t, but 3 of the 4 wheels (alloys) are bent, so that’s the cause of the shaking.
Kudos to Tire Discounters, because to determine the problem they had to check the alignment, then do a balance check and even put new weights on the wheels to help a little. I didn’t even buy the tires on the Mazda from them. Total charge - ZERO! They wouldn’t even let me tip the tech. So I highly recommend them.
Anyway, where can I buy inexpensive wheels in the Cincinnati area? I don’t know any 17 year old guys, who all probably know the answer.
I bought mine at my local tire place, and just explained that I needed something cheap that looked ok, but didn’t want anything fancy.
You might look on Craigslist, or at a wrecking yard though if you’re short on funds. I sold a set of truck wheels and tires for $200 on my local Craigslist last year.
I heard somewhere that Tire Discounters are pretty good. 
I recommend Tire Rack (tirerack.com). The have wide selection, a simple selection process that can actually show you what the wheels will look like on your car, and cheap shipping.
A couple years ago, I bought a set of five SSR 17" alloy wheels (a discontinued model) for that had retailed for about $500 each, and paid $950 delivered. (I got five in case I damaged one on track. They’re my track wheels.)
I had a pothole dented Wheel on my Alero a couple years back. I was able to order a replacement online for about $100, a bargain compared to the ~$300 the dealer would have charged me. I had it shipped to my house and the tire installer mounted it onto the new rim for me free of charge.
The boxes are big and bulky but not particularly heavy so the shipping wasn’t prohibitive. I’m not sure what you mean by “cheap” but there’s no shortage of places online to get this and something like a wheel is pretty tough to screw up.
I’d guess that buying 3 replacement OEM wheels online will be cheaper than buying 4 aftermarket wheels at any store.
Your other alternative is to call all the pick and pull junk yards and see if they have your make and model car on the lot or if they have the wheels on hand. Grab the Yellow pages and start calling.