I have played at several online casinos and know where you are going with wanting free cash.  There are some casinos listed here that give 300% and even 400% on your first $50.00 deposit. That gives you $200.00 to $250.00 to play and win with instead of just $50.00.  There are even some that give no deposit required bonuses.  I just love the games that Microgaming offers.  Here are some of my favorite cartoon 5 reel slots.

Moonshine - has 25 paylines, and a bonus spin game

Isis - 25 paylines and 20 free spin bonus at 6x pay for wins

What on Earth - 9 paylines and a great beam 'em up bonus game where you can even earn another bonus game.

Check them out here  http://www.cathy777.com