Oh, I dunno...my basic partial mash batch these days involves 4 lbs. of grain from lhbs for $8, 5 lbs. of dry extract (in bulk, on sale, from label peelers) for about $12, 3 ozs. of hops (in bulk from eBay) for $4, and about $3 for yeast (usually repitching one or twice).
Since I get about 26 to 28 bombers from a batch, that's about a buck a bomber. (Goes up and down according to style of course.)
That's considerably cutting my cost over the $5 to $9 I'd pay for a bomber of decent beer in the store. Doesn't factor energy costs, of course, but in the winter the boil actually helps heat the house. (And makes it smell nice.)
But, with rinsing/saving yeast, and buying grain and hops in bulk (and growing my own hops!) I just made 11 gallons of cream ale for $16. I got the Uncle Ben's rice from the Dollar Store, and used cornmeal from the grocery store. The two-row was $37 for 50 pounds (way more than I needed for this batch, but I used the per pound cost to figure the batch cost). The hops I grew myself, and the yeast was saved from a batch of California common.
So, yeah- $16 for 11 gallons of beer. That's a cheap beer to make and buy, typically. I generally spend about $25 for a batch of IPA (again, 11 gallon sized batches).
That seems cheap. But I have a good $3000+ into my brewing equipment. Most of it isn't necessary, but it makes brewing easier and more fun.
So I suppose you can save money by brewing your own, but it's a hobby so I don't count the savings OR the costs. I just simply like my beer, my kegerator(s), my brewing system, and brewing itself.