I went through a bunch of stuff just sitting around and here is what I am not using.
Two each - Marinco L5-20P locking plugs $10 each - SOLD
Two each - Marinco L5-20C locking cord connectors $10 each
Two each - Hubbell Elastogrip 5-15P straight blade watertight plug 14W47 $12 each
Two each - Hubbell Elastogrip 5-15C straight blade watertight connector 15W47 $12 each
Shipping based on what you buy, I can fit four items in a Priority Mail padded envelope for $5.95