"Frozen concentrate grape juice?" you gasp in shock.
Yes frozen concentrate grape juice. I had previously read that you couldn't use it to make wine, but I have since disproved that to be a myth. It certainly does ferment and well.
Each frozen concentrate grape juice container makes approximately 48 ounces or one quart of juice once rehydrated. Cost per quart $1.86. Cost per gallon $7.44.
You will also need one packet of winemakers yeast, though I have heard that you can use breadmaking yeast. I should do a post about that experiment sometime. Amazon has champagne yeast $7.99 for 10 packs, cost per pack is $0.79.
You will also need a fermenting bucket or carboy and an airlock. These are not different from the beer brewing supplies and so are cheaper to buy them that way. They are one time purchases and pay for themselves after a few batches.
Place the room temperature grape juice in the brew bucket. Add yeast. One packet of yeast will brew about 5 gallons of wine. No need to stir. Put the airlock on. Wait 2+ weeks.
Total cost for one gallon of wine equals an astounding $8.24! Beat that, box wine. Plus, since you didn't add any sulfates or problems the homemade wine is a lot more natural than the storebought bottled wines.