Here is a cheap air pump that might be good for a Roadster. The 15 amp fuse suggests it would be OK for the Roadster.
Note the warning not to use the fluid due to the tire pressure monitering system.
Slime Smart Spare Tire Repair Kit $9 + Free Store Pickup - Sears Deals, Coupons and Promos
Note the warning not to use the fluid due to the tire pressure monitering system.
Slime Smart Spare Tire Repair Kit $9 + Free Store Pickup - Sears Deals, Coupons and Promos