Campaign Creations

Im making a map that allows you to buy additional units by walikng on diffrent beacons it creates the unit but won't subtract any money
im using
Current player brings atleast 1 of any unit to carrier
Current player accumalates atleast 100 minerals

create 1 Carrier for current player
subtract 50 minerals from current player

also how does the "current player" work

For current player it simply uses the player or the force that the trigger is filed under. When you first make a new trigger, you choose who the trigger executes for, thats what the current player looks to.

You're typically better off making each trigger player dependent instead of "current player" if you're having any problems.