If you are playing in a low level cash game like a $1-$2 no limit many casinos have a maximum buy-in. However if someone has been winning at the table for hours they may have a significantly higher number of chips than the maximum buy. Many people are afraid to come in with a short stack say $100 when many of the players at the table have 5x’s that amount.
While it is true that in some ways you are at a disadvantage with the short stack, if you are disciplined and getting cards it can be a good opportunity to win a lot of chips with a smaller downside. This is not the time to do a lot of bluffing nor is it suggested that you call small bets and whittle away your stack.
You are best off waiting for good cards and then making bold moves. If you are not getting hands you really have to be folding but if the cards are coming your way with a lot of chips on the table you have a good chance of having a nice win even starting with the small stack.