Samsung sch u340 free ringtones?

i have a samsung sch u340 and it is currently on cricket wireless. i want sum tones but u have to add money at a store and i would rather add it to my bill. do u know where i could get tones for free that will add it to my bill or just give it for free. and also note that i wuold like to know if u go to the site on ur phone or computer. i,ve tried a LOT of sites and some wont download or some dont support cricket or when i download them, they dont play. i just want sum tones so please help. i would prefer if u've tried the site urself.