if you absolutely must be a nit and not load real money, then it is very easy to work out how much "rake" has been "paid", you start the session with x on the table between you, you end with a smaller figure y on the table between you. x-y = "rake paid", add half of that to your end stacks when settling
A group of friends from some of the local pinball leagues host small tournies all on Stars Home Games. Buy in can be as low as 215 Play Chips and you get 15K every 4 hours for refills.
I agree, pokerstars homegames seem best.
Also as @UncleJAthletics said, there been lot changes for play money reloads and play money buyins in homegames.
I'm just looking for a site that will allow myself and a group of friends to play online for fake money (they are nerds that don't gamble). Can anyone recommend a site that works for people in the US and for MAC? I know PokerStars has the Poker Club feature, but I'm in the US and the special software it requires me to download only works on Windows. Does Ignition or Bovada offer some feature like this? Any other recommendations?
From a quick first look, it appears to be a very well set up play money site where you can play against friends, on camera, or practice on your own against bots.