This is the most popular version of Video Poker.  Basically, you need to get a pair of jacks or better in order to get paid(hence the name).

Let's assume you bet five coins.  If you get a pair of Jacks or better, you get five coins back.  The machine might call you are "winner," but don't be fooled.  You deposited five coins to begin with, and you just got your original five coins back, so you haven't won anything at this point. 

In order to really win, you must get a two pair or higher.  The amount of coins you win depends on how high your hand is.  A typical payout schedule is shown below. 

*There are two types of machines.  One will pay you a straight number of coins for the Royal Flush, and the other will pay you a Progressive Jackpot.  A Progressive Jackpot simply means that a percentage of each coin dropped in the machine goes into a  jackpot, which is paid out to the next recipient of a Royal Flush.