what does it take to brew your own beer?
$100 - $200 in equipment, plus $30 - $50 per 5 gallon batch for ingredients.
From a time perspective, it's pretty spread out, and depends on the method you use. Most people start with malt extract brewing. Figure 3 - 4 hours on a saturday to boil. Then, about a week later, an hour or two to rack. Then, a week or two after that, 4 - 5 hours to bottle. Once in the bottles, it sits for a few more weeks, and it's drinkable. Of course, time and cost will vary depending on the approach you choose and the style of beer you're making, but that's a good general guide.
The biggest rule, the biggest time commitment, and the ultimate key to success, is cleanliness. EVERYTHING needs to be sanitized.
In the end, it probably works out to around fifty cents a bottle. When you compare that to some "average" craft brews (say, Sierra Nevada Pale Ale) that might sell for $8 per six pack, you're going to save money. And the beer is going to come out exactly as you want it to, rather than how some company thinks you want it. Even with "simple" extract brewing, it's possible to make beer significantly better than what you'll buy in most stores, as long as you use quality ingredients and can follow step by step directions.
If you're really interested, I'd find an experienced homebrewer on here that's close by and help them with a batch so you can get an idea of what's involved.