USAGE:
General:
EXCHANGE (object you are selling) WITH (player) FOR (object or cash)
EXCHANGE CANCEL to cancel an exchange you have proposed.
Specific:
EXCHANGE (noun) WITH (other player first/last) FOR (dollars)
EXCHANGE (adj) (noun) WITH (other player first/last) FOR (dollars)
EXCHANGE (noun) WITH (other player first/last) FOR (object)
EXCHANGE (adj) (noun) WITH (other player first/last) FOR (object)
NOTE: You may use "my" to further specify the item you are selling.
example: MY gun or MY water gun