really if you want cheap and easy and dont care what they look like, some cheap hub caps covered as stated above in duct tape would be very simple and cheap..or use expanding foam and fill any holes, the sand down the excess in exsisting hub caps and then coat them with fiberglass resin to harden the surface..
Sorry, I found more used for this expanding foam than I know what to do worth.. it's super light, shapes well, and strong too.. and cheap as hell one little can has a huge amount of "space" of finished foam in it.. i was even debating doing some of my under body in it... would make for a super quiet ride..
__________________
|