We use a lot of soymilk in my home--about 2 gallons a week. Two gallons costs about $14, for the Silk Unsweetened kind. I realized that was, almost unbelievably, well over 10% of our entire food budget!
I bought this soymilk maker for about $140 (much, much easier to clean than older models, like I had about a decade ago before giving up on it after less than a couple of weeks using it) : "Soyajoy G4 Soy Milk Maker and Soup Maker - Largest capacity, with All Stainless Steel Inside" and 13 pounds of Laura soybeans for about $25 (easy to find coupons online to save $5).
The 13 pounds of soybeans should last 6mos to a yr--not sure yet.
Savings: $14/wk X 52 weeks/yr = $728 - $25 for the beans. (The breakeven for the cost of the machine will be 2.5 months.)
Bonus: you get lots of okara (soybean pulp) which is very healthy, and can be used to cook all kinds of stuff, and replaces tofu in many things. For instance, I can now make an okara "meatloaf", that supplies six adult servings of food for less than $2 in other ingredients.
Another bonus: you get to control what goes in your soymilk. You can also make other kinds of nondairy milks.
There *is* a trick to making it so that it doesn't taste "beany" (a flavor that apparently the Japanese really like) and is very neutral/bland, like Silk. Namely--don't cook it like the instructions say. If anyone is interested, I can give you my recipe, which works flawlessly.
Drawback, it takes about 30 minutes to make about 1.7 quarts, though only about 5 of that is active time. I do it while I'm already doing other stuff in the kitchen, and I make 2 batches back to back, which lasts us a few days.