Answer: As many as possible.
mobile17.com lets you make your own ringtones using .m4a (iTunes) and .mp3 files. For Free! The only cost is like whatever it costs to send a message to your phone, which is a hell of a lot less than buying ringtones, and you get to choose where the song begins and ends. So far I've made 6 ringtones:
Fight Song! By Joe Firstman ("I threw 100 punches, got this big black eye, I got banned from Indiana, felt like I was gonna die, so I screamed 'rah rah rah rah rah... You should have seen the other guy!'")
The Frug by Rilo Kiley ("And I can hate your girl. I can tell you that she's real pretty. I can take my clothes off. I cannot fall in love. And I can do the frug. I can do the robocop. I can do the Freddie. I cannot do the Smurf. She cannot do the smurf!")
One Line by PJ Harvey ("I'm watching from the wall, as in the streets we fight, this world all gone to war, all I need is you tonight. And I draw a line to your heart today, to your heart from mine, one line to keep us safe.")
Better Son/ Daughter by Rilo Kiley ("And sometimes when you're on, you're really fucking on and your friends they sing along and they love you. But the lows are so extreme that the good seems fucking cheap and it teases you for weeks in its absence. But you'll fight and you'll make it through, you'll fake it if you have to, and you'll show up for work with a smile.")
Portions For Foxes by Rilo Kiley ("I know I'm alone if I'm with or without you, but just being around you offers me another form of relief. When the lonliness leads to bad dreams, and the bad dreams lead me to calling you, and I call you and say C'MERE! And you're bad news...")
Glendora by Rilo Kiley ("It's New Years Eve, I'm in Glendora, I'm the only living person in Glendora. Heading East, on the freeway, I left my prom dress at a bus stop in Duarte. I switch the rules, you take advantage, you know I always like to play the victim. And would you fuck me, 'cause I'd fuck me. Am I your wetnap? Freestyle walkin'. I cry cry cry then I complain come back for more, do it again.")
I should probably stop sometime soon, but I just can't. At this rate I'm going to have more ringtones than phonenumbers in my phone.