i looked up hotels on orbitz, and the cheapest in SPI is $140 a night and thats just too much for me and my still-in-college sister. march is spring break month, so thats probably why its more expensive than you thought. and where do you fly into? i typed in south padre island, and it came up as a flight to brownsville, tx, and prices start at $350. yikes!
i was thinking of staying with friends in miami for a day or two, hitting up the cable park, and then heading down to key west, where i think the wind is more consistent. also there's a hostel you can stay at for about $30 a night (which might fill up fast b/c of spring breakers). the bad thing is that the cheapest flights are into ft. lauderdale, so you pretty much have to rent a car.
the only kiter i know there is paul menta in key west, who i took lessons with about 2 months ago. he has a "kitehouse" which sleeps 4 that he rents out for $85 a night, but i emailed him trying to make a reservation, but still haven't heard a response.
im definitely not ready to go out by myself, so would love if i could meet up with a kiting buddy. if i cant do that, paul does supervised rentals for $100 a day, and will take you out on his boat to the "secret spots", but like i said, he's not responding to my e-mails, which is annoying me, so i havent booked a flight yet. let me know what you guys wanna do.