Man, I know what you mean about cost...
Dupli-Color High Perf (UV) Silver Metallic - 300 mL rattlecan $10
Candy Clear - 1 Qt PPG Acrylic Urethane Base $55
Yellow Dye - 1 Pint PPG dye $128
Red Dye - 1 Pint PPG dye $128
PPG Polyurethane UV Clear Topcoat - 1 gal $200
Should be enough material to paint the tank, covers, ears, and headlight bucket about 100 times over.
The paint guy gave me a great idea for saving time and money:
1) Use Mylar (or plastic sheet for the cheapies, but the paint won't dry as well as on Mylar) and lay down one layer onto each sheet and enough sheets to build up the colours.
5) If you want metal flakes, mix flake powder into the clear base and shoot one or more Mylar layers with no colour but with flakes
2) Combine the number of layers you need as overlays to see which combo is closest to the final shade.
3) Because the film will add its own character, so to be sure its the right combo, shoot a final test swatch using your selected combo onto a Mylar sheet.
4) Since Mylar is flexible it will bend around curves to show the final result more accurately.
Using this approach, several different silver layers can be compared with any number of yellow layer, metallic layer, green layer, red layer combos.
The example I gave in an earlier post would be (1) Dupli-Color Silver Metalic layer + (1) Red 30:1 Clear layer + (1) Flake layer + (3) Yellow 10:1 Clear layers + (1) Top clearcoat.
Had I thought of this earlier, I wouldn't have to be ordering my next batch of paint