Before making your buy-in, you'r going to have to figure out where to
get the money to do so. That money will come from your bankroll, a special
fund you set up exclusively to be used for gaming pursuits.
The size of your bankroll depends on how much money you are willing
or able to set aside for this purpose. The general rule of thumb is to
have a bankroll of between 10 and 20 times the size of the average buy
in. With the advent of online betting, it is possible to work with much
less as you wont have to deal with crowded tables, high bet minimums,
travel expenses and most importantly the pressure to act quickly.
But if you want to play it safe, then the ten to twenty times rule stated
above is probably best.