I think it depends where you live. Around here, any half-decent craft ale is up to at least $10-$12 a sixer. Cost-wise I can beat that all day long.
Since we're comparing bulk purchased homebrew ingredients, we should compare bulk purchased commercial beer. Most beer is a usually a little cheaper than that by the case, and certainly cheaper by the keg. Per batch, homebrew ingredients are still much cheaper, but that does narrow the margain some.
For me, personally, I've spent about $1k on my brewing equipment and about another $1k on the keezer in year that i've been homebrewing. I could have been cheaper than if i wanted to, but I'm far from having an over-the-top home brewery that many people here have.
Now, with extract ingredient kits that i started with, i paid $30-40 for a 5G batch. With all-grain, I'm in the range of $12-25 for a 5G batch. I brewed four extract batches before going all-grain, and ten all-grain batches now.
Before i started brewing, i was buying commercial craft beer in 1/6th barrel kegs. When i started brewing, i figured that i saved about $50 brewing my own extract batch over buying a craft beer keg. So, i'd be saving about $70 on an all-grain batch. So, total, I've saved $900 making my own beer vs buying craft, which has just about paid for my equipment other than the keezer, not bad.
That assumes, however, that my time is worthless, which it certainly is not. An all-grain brewday for me is probably 6-7 hours of brewing and cleaning that i spread out over 8-9 hours. Then add another couple hours per batch for checking on fermentation and kegging, and I easily spend 8+ hours on a 5G batch. So, even after my equipment costs are paid off, I'm brewing for about $8.75/hr in savings, just a little above minimum wage. Extract batches are much faster, the hourly rate in saving over buying craft beer might be a bit higher. Count the amount of time i spend reading homebrewtalk and planning batches and my hourly rate plummets to probably under $1/hr.
Now, there are several inaccuracies in my calculations. I could sway the numbers to make it look like i save more or less. I could make larger batches which wouldn't take much more time per batch and significantly improve the hourly savings rate, but would mean a little more outlay in equipment. I also give away a bunch of beer, killing my savings.
The thing is, for me right now, I don't count the hours i spend on brewing. It's a hobby that i'm enjoying. I use the cost savings over purchasing craft beer to keep my purchases on equipment in check, but that's just a guideline, not a rule. As far as hobbies go, something that pays for itself and entertains me for a few hours a week and almost a full day every few weekends is pretty good.
So, bottom like to the OP, if you're enjoying brewing and keep your spending within reason, you're not going to break the bank on this hobby. If you're trying to save money on beer by brewing your own, you could probably find a part time job that would do better for you or find other ways to save money around the house that will take a smaller initial outlay of money AND save you more in less time. I'd probably save more money per hour spent knitting sweaters and turning the thermostat down a few degrees in winter, but i enjoy the brewing.