I am a low roller and I usually only deposit like $20. My fear is winning $50 and then finding out the casino won't let me withdraw anything under $100. Which sites are friendly to small players who just want to cash out small wins?

You need to check the banking terms before you start, but many listed sites are good for this. A typical crypto Plinko Casino will often have very low withdrawal limits, sometimes as low as the equivalent of $10 or $20. Platforms like N1 Casino or Drip often cater to casual players, so you aren't locked in until you hit a jackpot.