1. Find someone with the same phone and have them back up their ringtones to a computer or microSD card, then transfer them to your phone (or use an app like WiFi File Transfer to transfer them).
2. Go to Zedge and you'll find more ringtones than you know what to do with (all free).
(Clearing cache doesn't delete anything you need - it's data that apps need, most of the time that they forgot to clean up, because the developer was a bit sloppy in writing the app. Clearing data is clearing the stuff you want - emails, texts, ringtones in your case.)