Have you tried all those websites that people suggest all the time? Like funformobile.com and doing it the OTA way? It's probably a stupid question but I just like to make sure that you really have tried EVERYTHING, ya know?
there are free ringtone sites out there, you can actually get ringtones for free here at crackberry. the easiest way i've found is to access the sites directly on my berry and then they just download straight to the phone. but a memory card would be a good idea, it helps with the storage room.
I downloaded mine from right here at crackbery.com. The library here is pretty good. I've also noticed that periodically some kind soul will pop up here at crackberey and offer to custom make them. If you need help search ringtones at crackberry on google.