There are a lot of tools that can help you make custom ringtones, you don't need to buy them. That's a really expensive way to go for ringtone variety.
If you are a Mac user, try mac iPhone ringtone maker
A lot of iPhone users have problem syncing iPhone ringtones. Some questions are like "I can't sync ringtone to iPhone", "it shows up as a ringtone in iTunes, but it won't sync to the phone. I've restarted my phone several times, hoping that would do it. I've removed all my ringtones, then...