I have a large Budweiser bottle bank sitting on my kegerator. When I would buy a keg of commercial beer, I would multiply the cost by 1.5 and then divide the total by the number of servings. Then, everytime I'd get a beer, I'd put the money in to save for more beer or equipment to start homebrewing. Imagine my suprise and horror to find my father pitching $$ in when he'd get a beer. Never told him he had to, never expected or wanted him to. Told him to knock it off, the beer is free to him. So, now when I put money in, I put the whole amount in at the beginning..... He doesn't see me do it now, so he doesn't do it either. I do the same with my new batch of homebrew... supplies times 1.5. After a few batches, I'll have a few more bucks saved up and begin to shop for new toys to brew with.