Pet rats! My time has come!
Things always go in and out of fashion with pets, but my go-to was always oxbow's rat food. NOT their mouse and rat formula, this one:
https://m.drsfostersmith.com/product/prod_display.cfm?pcatid=16965
Cardboard boxes and fleece will be your best friend

honestly as far as toys go I stopped bothering to buy them. My boys' favorite thing was a toilet paper roll with food inside! And tissue boxes to hide inside of.
They're awesome animals. One of mine even went to a college class with me to do a public speaking presentation - everyone thought he was a ferret! How do you even mix that up??
eta: If you do end up looking for a friend for him, please consider a rat rescue! Yes, they really exist - and there are tons of boys out there in need of homes! Since you're in Indiana, Mainely Rat Rescue might be able to help you find a local rescue or you might be able to get a rat train going to transport one of their lovely rats to you. They also offer neutering/spaying already for their lovelies who are young enough.
There's nothing wrong with pet store rats, either, but I just wanted to point them out because so many people don't KNOW there are rats out there in need of homes already! All 4 of my boys were from pet stores, actually.
I won't harp on the stuff that's already been said a ton of times - I'm just super happy to see you're getting a multi-level cage and a friend. You're going to be a great rat parent.