I purchased windows 10 enterprise for my new gaming pc but I can't find where to download the program to a usb. I only see Home and Pro available to be put on flash drive so I am curious if I just wasted 50$ on a key?

You need to prove to Microsoft that you are a business, first.

You can only purchase enterprise through a volume licensing agreement, you can't buy it retail. The key you paid for is probably pro.

He didn't buy from MS, he bought from one of those sites...like Kinguin or similar.

Ghot made me think about it more. If you really did get an enterprise licence, then use the pro download. The only real difference in the two is how it's licensed and what happens after activation. Things like branchcache and applocker can be enabled after activation, although I don't think you'll find any good use for them at home outside of a learning lab environment.