I wouldn't advise the spray paint route either. It will cost you way too much for good automotive paint and at the end it will crack anyway. I did it for me and me girl when we picked up old rossignol board that went out of rental for free so I didn't mind spending ~$50 on paint and supplies. It turned our great but still chipped in the end. Make sure to coverup the binding mount points before you spray though.
I cut out a couple spades for myself and a heart for my girlfriends board as stencils and the boards in the back WALL is what I came up with. Not too bad but I was young so I just wanted to ride and not have "Rental" in huge red letters on the board. (excuse the cut outs in the wall, basement got flooded a few days before I took this picture in March).