Hi ya gjr1961, I guess an answer to your question is, it depends on the casino's terms and conditions and the luck you have. lol I know its a bad answer but ... here's what I've experienced.
For the casinos that ask that you make a deposit prior to you being able to make a withdraw ... I've been fortunate to have this happen twice at Microgaming casinos and after making the required deposit, the first time I probably gambled about $5 of my deposit and withdrew the rest of my deposit plus the winnings from the free spins. The 2nd time after making the required deposit, I thought I was on a roll ... and ended up loosing my winnings from the free spins and my required deposit. lol
One thing to remember is before you make the required deposit, please read the terms and conditions carefully, you may of made the play through on the free spins but sometimes casinos put a playthrough on your deposit also. If their terms and conditions are confusing to you, always contact the casino and ask them to explain them to you. And .... don't be embarrased to ask, its your hard earned money we're talking about.
It is definitely do-able even though the playthrough seems way to far from reach, you are playing with free money, its not costing you anything so why not try it. I love freebies and I've cashed out on quite a few of them too. The largest cash out I've ever had was $3,750.00 and it was from a $10 freebie. The 2nd highest cashout I've had was a 30 x playthrough of my bonus and deposit. I hope this helps!!
Good Luck hun!
Happy Gaming Always!
OrangeCrush