I'd suggest having at least 30 buy ins to start a level. Some people insist on 100, but I think 30 is enough. I started $1.10 SnG with $30, then the $3 SnG at $100.

It's important to have a lot of buy ins, because bad variance CAN and will get you, no matter how good of a player you are. You gotta have the cushion to stick it out. If you move up ranks quickly, you will bust out.

When you're in the micros, don't think of it as making money, think of it as gaining experience. You want to stay there as long as you can.