My pup's favorite thing when he was teething was totally homemade and cheap... I took an old ice cube tray and filled it up with his kibble and a few tiny chopped up pieces of carrot. Sometimes I'd include other fun things, like a pea or two per cube. Once the cubes were "filled" with food and other edible solids, I'd pour water in on top then freeze them.
Nikko never liked plain ice cubes, but he adored those frozen food-cubes like godzilla would adore a skyscraper-sized chunk of veal. Gross, but awesome. They never had the chance to get too messy, because he ate them start to finish in one sitting, and never let them melt too much.
Lauren & Nikko