Several casinos now offer a 100% match bonus that is credited directly to your balance.
You deposit 100 and play with 200
Requirement only kicks in if your balance goes below your deposit.
If your first spin wins 1000, your balance will be 1200 and 1100 is completely withdraw-able... the 100 insurance bonus would disappear .
If you start losing and balance goes to 99.99, the bonus requirement kicks in...if by chance you win 1000 now, sorry... its all bonus money until you meet the requirement.
These are the best bonus offerings that I have seen.
That extra money that you are starting with is technically nothing unless you lose your real money first. Insurance...