I save a load of money making beer.
For a 2.5 gallon batch, which is roughly a case (which I definitely don't do, but this is scaled down for Mr. Beer equivalence):
6lbs grain - ~$6 (50lb sacks at under $1/lb plus some specialty)
yeast - $6 for liquid, about $3 for 1/2 a pack of dry (assuming you don't do anything to propagate or harvest, which I do--so free for me unless it's a new strain)
hops - $1-2 (by the pound)
So... you're looking at about $8-14/case of beer, compared to (non-craft) commercial, which is at least $24-30/case.
If you are thrifty, you can get by with almost none of the things people tell you you "need". A used 7 gal aluminum kettle with a weldless valve already in it cost me $25 on craigslist, and I fit a stainless mesh into it (scrounged from a $10 part) and a barb fitting for my valve ($6) plus various tubing ($10-20ish). That's my boil kettle and mash tun. Add an autosiphon and maybe a bottling wand ($20-30), a
good waterproof probe thermometer ($25). Hydrometer, of course, if you don't have that ($15-20). Most people can fudge temperature control (more or less) without equipment, but you need that for Mr. Beer too. If you have a deep basement you might be good all year, though I use a $15 aquarium heater with a thermostat in a big tub of water to get my buckets up to fermentation temps.
I mean you're talking about a $100-150 bare-bones setup before ingredients, but if you buy any real quantity of commercial beer you're going to recoup that in the year or sooner.
Now, the real danger is that you might start to get excessively interested in really good commercial beer, and that's where it starts to get expensive. But then you can learn to make that too.
The bottom line though - the ONLY way to make beer cheap is you have to buy ingredients in bulk. You can't pay $2 a pound for grain or $2-$3 an ounce for hops and use $7+ yeast one time and think you are going to brew cheap.
That IS the bottom line. Maryland's bulk base grain scene is not so good, so when I'm traveling I look around. In Durham, NC I found I could get sacks of Rahr/Briess for $0.79/lb. So I came back with 100lbs. Next time I go I'll probably get another 100lbs. Even if you can only get it around $1/lb (standard in MD), you save 50% off the cost of "scooped" grain by getting a 50lb sack. If your LHBS won't do sacks you have options on Northern Brewer for about $1.10/lb shipped (Rahr 2-row, anyway). That was my first source.
Meanwhile, my chest freezer is mostly full of hops. Let's just say my family thinks I'm pretty weird. Anyway, you don't have to go as far as all this, but let's just say you're better off picking one base grain, buying 50lbs of that, picking one or two hops, buying a pound each of those, and then learning to recycle your yeast effectively... and you can make really cheap beer.