You need to get to Wal-Mart! Can you swim?
Bburago and Maisto are the big players in 1/24 diecast kits (Bburago kits are superior quality) Testor's markets both under its name, too. RC/Ertl, Racing Champions and American Muscle are all related and offer kits, too. Revell also offers diecast, like the Vanishing Point Challenger kit. They go together well, with assistance from an adult, though. Bigger kits in 1/18 scale come from RC/Ertl/Racing Champions/American Muscle and others less well known, but can be more difficult to assemble. I bought one new Ford GT as a kit (also available assembled) and wondered how they could possibly make it in China on an assembly line without going nuts.