iPoker (informed Poker) is a free online Texas Holdem poker app that shows your equity while you play with other players. You can use this information to make more informed decisions (hence the name).
The app also shows the largest bet amount that results in a positive expected return (if such largest amount exists). If all bet amounts result in positive expected returns (i.e., when you have a large equity), this is not shown on the screen. When this value is shown on the screen, betting as little as possible results in the largest expected return, and betting more than the amount shown in this box results in negative expected return.
Note that the above statements are probabilistic, meaning that they should be interpreted as fractions or average winnings over a large number of trials. For example, a preflop equity of 85% for pocket aces with two players means that if the same hand (of pocket aces) is played a large number of times (e.g., one million times), then roughly 85% of the times (i.e., roughly 850,000 times out of those one million times), the pocket aces will win the pot. In other words, even in this very favorable scenario, there is 15% chance of losing (150,000 out of the one million in the example). In general, even with very high equity numbers, a given hand may end up losing in a single trial.
You can play simply by choosing a screen name. Your winnings and other stats (such as hands played and biggest win) will be available to you as long as you continue using the same device with the same account info. You can optionally add a login name and password when you create your screen name, in which case you will be able to carry your winnings to any other device.
You can select the stakes (small blind, big blind, and buy-in), as well as the game speed (relaxed, normal, or fast). The buy-in amounts range from as low as 1000 to as high as 1,000,000,000.
You can let the server pick a table for you based on your selections, or you can create or join a private table to play with your friends.
When you first join, you receive 100,000 free chips. You can get more free chips by watching a short video or inviting a friend, or you can purchase additional chips to be able to play at higher stake tables.