Tournament Bankroll Management

[Nelob]

I am a fairly decent poker player and I have won about $2000 player poker tournaments but I cashed out a few months ago and now I am looking for a new start. I started playing freerolls on absolute poker and I have managed to get my bankroll up to $3. I am strictly a torny player and I never play cash games. I am wondering, what amount of my bankroll should I be risking on each MTT or SNG. I have heard that 5% is right but I am not sure. Any comments?