LOL we can help you part with your mon... err um get geared up!
Most large ops will let you know what style of BDU you should wear. in OP:LC5 I think it was Desert vs Woodland colored BDU's.
Gear wise you'll need the following minimum:
Chest Rig (Anything holding the larger magazine pouches)
Hydration Pouch + Carrier
Approved Googles/Full Mask (Depends on game rules)
As mentioned in other posts, there's a bunch of options you can go after. Realistically go with whatever your event is calling for. You cna end up spending more on gear then your guns. It's a scary thought..