At the Arena, when players choose "Deathmatch"' and "Team Deathmatch" modes, they are allowed to bid.
Bid's maximum value depends on current level of a general that you want to use to participate in a particular battle.
There can be only one winner which gets everything.
After "Team Deathmatch" is over, the winner team's survivors share the prize equally.
Hint: You don’t need minibots or credits to take part in training combat. When you win, all resources collected on this setting, during combat with Aliens, will be added on as a prize.