the standard raise amount preflop is 3xbb +1bb per limper. If your playing in micro stakes where players call 3x raises with marginal hands, they're usually gonna call 4-5x raises as well. Save your chips and just raise the standard amount. If they are calling with worse hands, you will profit in the long run. Always keep position in mind as well. Alot of newer players are playing big pots out of position. This is a HUGE flaw.