I've fitted one of these, it was very simple and gives a good but not awesome effect. I got it as a father's day present so can't comment on the value but if you're handy and like to fiddle you could certainly make your own. If you're time poor just buy it

http://www.ebay.com.au/itm/Addams-Family-Pinball-Swamp-Hole-Kickout-Light-Mod-NEW-/281199630508?pt=UK_Video_Games_Coin_Operated_MJ&hash=item4178cdd8ac