10nl and up you can only buyin for 100bb. At 2nl (.01/.02) and 5nl (.02/.05), PS lets players buyin for 250bb. Why?? I don't know, but you shouldn't worry about it. Buyin for 100bb so you can learn to play with a 100bb stack, as that is what you will be using at 10nl+ (I assume). Letting the donks at micros buyin for 250bb shouldn't be an un-level playing field. It's just more money on the table for you to take, as I'm sure most don't play a deep stack correctly.