With unlimited money maps, you need to be sure that the money crates only spawn when there is no money crates in the area. This way, there will only be just one money crate there. It sounds like in your map, the crates just keep spawning forever on end, causing the extreme lag.
So your scripts should look like this:
*** IF ***
Player 'PlyrCivilian' has Equal To 0 unit or structure with Kind is 'CRATE' in the area 'Money Area 1'
*** THEN ***
Spawn unit of type '2500DollarCrate' on Team 'TeamPlyrCivilian' at waypoint Waypoint 'Money Spawn 1'
The condition is located at
Player\Owns\Player has (comparison) kind of unit or structure in an area.For the action, it's
Unit\Spawn\Spawn -- unnamed unit on a team at a waypoint.For the Script Properties uncheck "Deactivate upon success". This will allow the crates to spawn forever on end as long as the players is collecting the crates. Leave all the other options as default for the Script Properties.
The condition I used might confuse you. Every object in the game has a "Kind of" setting. These settings define the objects of what their capable of. The 2500DollarCrate, only has two of them, "PARACHUTABLE" & "CRATE". So if you change the "CRATE" in that condition to "PARACHUTABLE", it would work too.