justwin has it right. They will match your deposit, but only 10% per bet at a time. So, if you deposit $100, it would take you 100 $10 bets to reach that match. It\'s a nice gimmick, since you never have $0 in you account. If you bet your last dollar, you end up with 10 cents in your account.
Fell for it myself. I use twinspires and tvg now. Eventually DRFbets, Twinspires, et al have much better deals - so I\'d hold out for a $500 match from one of those.