I started off with the synthetic stock from my Mossberg 802, wiped it down with laquer thinner to remove any oil or whatever may be on it, then i scuffed it down with a red scotch brite pad to remove the shine and rough it up so the paint would stick better. i wanted to do sort of an urban camo color scheme(light gray and dark gray) i taped off the checkering and painted the whole stock dark gray.when that was dry, i added light gray stripes, it doesn't matter how you do this, i just did mine diagonal
while the stripes were drying, i cut up a new dish sponge(little one with a scrubby side) but any sponge will do. i cut it up into about 1 inch sections, i made 2, 1 for dark gray 1 for light.you want to sponge with the opposite color(light on dark, dark on light) there is no set pattern, just do what you feel like, it's kind of "goof proof" (i think anyway)
while that dried,i made a skull stencil from a pic i got from the internet and added the skull but didn't like it all black
so i used some dark gray over top to give it sort of a shadow effect
then it was time for clear. i put 2 light coats, wet sanded with 2000 grit to smooth out(be careful not to sand through the clear) then put 2 more coats, let it dry for a couple of hours, then put it back together.
I just used Krylon paint from Walmart, i think i have maybe $20 in everything.