Very good advice from BW! the other thing is alot of clubs have a club trainer you might be able to get your feet wet with and decide if this is something you really want to get into..........and you will!

Also, i would be very surprised if someone in your local club doesn't have a good used trainer for sale cheap, especially if they're looking to recruit new members.
I wouldn't let that youtube vid scare you away from buying an alpha. That "pilot" would've ripped the wings off any trainer. They simply aren't designed to do sudden abrupt high G manuvers at wide open throttle like he was doing.
Good luck-rep