The cheapest thing to do would be to make your own sauerkraut or pickled veggis. I was just researching this yesterday, here are a few things I learned.
Buy some fermented veggis from this place (Cultured Vegetables - CULTURED VEGETABLES, SHOP-IMMUNITRITION ), and then use some of the juice as starter liquid for your own batch. Caroline said that when you use a starter that it can really cut down on the culturing time. Caroline talks in depth on how to make your own, using a glass canning jar at home, here: Dr. Mercola Interviews Caroline Barringer - YouTube
Here's a good jumping off point for researching at fermenting stuff. List of Fermented Foods & Vegetables that Can Heal Your Gut And a GREAT TED video about bacteria.
5' 10" | AGE: 35 | SW: 247 | CW: 229 | GW: 145-158-ish