I'm sure it depends on where you are. I did the reasearch for San Antonio. As far as costs, it's all over the chart. Most of the suppliers will help you set up your inventory. These guys could get you started: LD Carlson Wholesale Home Brewing and Wine Making Supplies
Also, any real estate broker worth their salt will give you a full marketing study including demographics, income, home owners, etc. for any of their buildings.
You can make a profit competing against the online stores, but you have to have local home brewers or have the time and money grow your market. Just remember, you are selling a product that is completely dependent on disposable income. You can tell by the comments on this board that your customer service has to be the best.
We elected not to do it at this time. Both of my "Partners" are in college finishing up their degrees and it would have taken too much time away for them or worked me to death. As luck would have it, we decided to put it on hold and a nice new shop openend just out of town about 3 - 4 months later. We will eventually do something brew related. I know this didn't help you with financial info, but opening a business in most parts of Texas is usually much cheaper than other parts of the U.S. (Not always, so you guys in Houston & Austin, don't get your feelings hurt) so a dollar figure will really vary from state to state. Luck - Dwain