$2 fine sanding sponge and $3 spray can. It won't last forever, but neither will the board. It can be cheap or expensive. I wouldn't worry much about the weight.
I painted a board over two years ago and it still looks good.
I sanded the board with a pretty fine paper to basically just rough it up. I taped out some designs on it and used 4 different colors of paint and then put a clear on top of it all.
I used Duplicolor engine enamel and then the clear engine enamel on top.
It has not faded at all. It does however add a good amount of weight to the board.
I think in all I used about 6 cans of paint including the clear.
thanks for the replies.
I started to repaint it, and for the moment it looks great. The old grafic of the Ronix Frontier wasn't nice for a girl anyway so I won't regret my choice.