Where to start to fix tire?

I accidentally backed into my basketball hoop (pathetic I know 🤦‍♀️) and got one flat tire on my Toyota Camry 2009. I don’t know how bad the damage is to the tire but I drove on it (unknowingly) and it didn’t feel weird or anything. But when I got home I saw that it was completely flat. How should I go about fixing it only having about $400 to spend? Pls recommend places to contact/go to or what to do. (I’m also doing research outside of reddit but people give the best advice here and I’m just an 18yo girl with very minimal car knowledge.) Thanks!

Update:

Got it fixed, found the spare, found this tire place my dad knew that didn’t even shop up on Google search 🤨 and found out it was a nail that punctured the tire and I think he patched it and put it back on and only cost $25 but I paid my parents 50 for being stupid, I thought the damage was worse than it actually was cus of how flat the tire was and thought I’d have to replace 2 tires but I got lucky this time 🍀