If you buy in for the maximum and are a good player, 10 buy-ins may give you a low enough risk of ruin. It depends on your playing style and table selection, though. Sometimes I decide to go after a weak player with a huge stack, and that produces higher variance.
You've undoubtedly heard of the 300 BB recommendation for limit play. That corresponds to winning about 3 BB/100 with a standard deviation of about 15 BB/100, for a bankroll that is 4 times the ratio variance/edge = (std dev)^2/edge. Here are some stats people have posted about NL:
Mosch claimed a win rate of 34 big blinds/100 and standard deviation of 97/100 with a $0.50 big blind.
AAmaz0n claimed a win rate of 15 BB/100 with a SD of 54/100 with a $0.50 big blind.
Guy McSucker claimed a win rate of 12 big blinds/100 with a SD of 60/100 with a $1 big blind.
If you assume these are exactly accurate, then at the analogous safety level of 4 variance/edge, Mosch should have a bankroll of 1107 big blinds, AAmazOn should have 778 big blinds, and Guy McSucker should have 1200 big blinds.
If you are desperate, I believe you can achieve more safety by buying in for less. You will probably sacrifice some EV/hour, but I think a much lower bankroll is needed if you buy in for $5 each time.