I got it for free because i own a copy of CS2 so all i had to do was enter my CS2 serial number in some thing that made it a CS3 one on adobes website then i downloaded CS3 and installed it and it asked me for a S/N so i gave it and then i had to register it (thats free i think all i had to do was click register then it was done) and then i could run it without an expiration
If you don't have a S/N you can get it from their website but only run it for 2 or 3 days i think
