Definition of add-on
When we talk about add-on in poker, we are in poker tournaments. It's an addition that you can make to your stack at a specific point in the tournament, often at the first or second break. This addition is never free and depends on the tournaments, but its price is often equal to the entry fee. It is very important not to confuse it with the buyback or rebuy, which is a mat that you can buy when you have lost all your chips. The add-on can be made at the same price for all players, no matter how many chips you have.
Example of a add-on
We are in a 10 euros tournament which gives us 1500 chips. After a few hands, we are all in and we lose all our chips. The dealer then asks us if we want to make a buyback. For 10 euros, we will have the same number of chips as at the start, 1500. With this buyback, we are lucky and we raise our stack to 50,000 chips. At the break, we have the option to make a add-on (or addition) for 10 euros. From that moment on, we will have to consider if this addition will be profitable for us. If the addition is 1500 chips for 10 euros, considering our carpet, it is not a good option. On the other hand, if the addition is 20,000 chips, it will be imperative to take it.