A rebuy tournament is one in which you have the opportunity to buy more chips during the event. In a standard ‘freezeout’ tournament, when you run out of chips, you're out of the tournament. In a rebuy tournament, you can (with some restrictions) buy more chips.
Registering for a rebuy tournament is no different than any other tournament at Rigel Poker and you will start with the same number of chips you would normally have in any other event.
There is a ‘rebuy period’ at the beginning of the tournament. A typical rebuy period might be the first hour of the event (until the first break starts). Once that period is over, no more rebuys are permitted. During the rebuy period, there may be a fixed number of rebuys available, or an unlimited number. If you run completely out of chips, you will automatically be offered a rebuy (if one is available). At any time when you have chips, you can click on the dealer tray and select the ‘Add More Chips’ option to rebuy. If you're not eligible for a rebuy (because you've reached the maximum number of rebuys, or because there is a maximum number of chips where rebuys are allowed), you'll get a message to that effect.
In general, you may rebuy using the ‘Add More Chips’ button in the dealer tray any time your stack is less than or equal to the starting chip stack. This means you can rebuy once before the tournament even starts! The rebuy may cost any amount, but generally costs the same as the original buy-in, and gets you the same number of chips that you got for your original buy-in.
There may also be an ‘add-on’ available at the end of the rebuy period. Typically this will be during the first break. An add-on is just one extra rebuy. In general, the add-on is available no matter how many chips you have.
The add-on may cost any amount, but generally costs the same as the original buy-in, and gets you the same, or higher number of chips that you got for your original buy-in. Rebuys are not charged a rake. So if a rebuy tournament has a buy-in of 10+1, then the rebuys will usually be 10 and all 10 of each rebuy will go into the prize pool. The prize pool and payoffs will not be announced until the rebuy period ends, since the prize pool increases with each rebuy.