Swix bricks last long and work great. Make sure you cover all your bases: yellow - spring slush, red - moderate temp, blue - cold. If it dips into the negatives fairly often, you may want to buy some green as well. Be forewarned though, its a bitch and a half to scrape.
Also, wax your skis whenever you see the bases turning white (base burn). This means your bases are dehydrated and need to be moisturized with wax. Wax itself is slow, which is why you're supposed to scrape it off completely, but if you'd hitting rails and such I would say just leave it on and it will smooth itself out after a few runs (unless you're using cold wax).