I started off with a gutted 17' Monark aluminum bass boat
Put down the base of self etching OD green
I made a set of stencils out of the large plastic yard sale signs. Available from Lowe's/Home depot/Wal-Mart, etc.
Laid down a series of random arches in flat white over the base OD green.
Laid down some flat brown thru the first stencil.
Then flat black thru the second stencil.
Flat tan thru the third stencil layer and some green thru a stencil of leaves.
Same to the motor
Finished and put back together.
All said, I think I have about $75 wrapped up in the camo (not including the OD green base). If I recall, I used 5 cans each of black, brown and tan. 2 cans of white. The yard sale signs were about $2 each.
Maybe this could give you some ideas for your own project.