Lotsa ways to control costs in the hobby, especially if you're not real particular about what you build.
40% off coupons, liquidation stores, and careful price comparisons online can cut kit expenditures in half.
Using automotive rattlecan paints gets you a lot more material than hobby-specific paints. There's a learning curve, but the cost savings can be substantial.
Airbrushing is another way to cut costs, once you get past the initial expense for the equipment. You'll use less material, and waste less. You can also decant and use "bad" rattlecan material.
Buying solvent "cement" like MEK in bulk containers (if you don't live in an overprotective mommy state) can save a chunk too.
EDIT: Nothing is ever going to get cheaper, so putting some thought into what you get for your money makes more sense now than ever.