Hi mea culpa! I'm currently an undergraduate living in college station, and hopefully this will help you (and anyone else interested in Bryan-College Station) out.
The cost of living in BCS is very affordable and student friendly. $23k a year should be more than enough even if you yourself do not obtain full time employment. The job market in College Station is not, unfortunately, ideal. The population of College Station practically doubles during the school year, and a fairly high percentage of students are competing for a very limited number of (desirable) jobs. I have an on campus job that's not work study based, but I think that's somewhat unusual. Nevertheless, the cost of living in BCS is below the national average.
There are a lot of different possibilities for housing in College Station. I've lived off campus with roommates for the past two years. Both years I've lived a little further from campus than your average apartment complex in BCS, and it has definetely payed off. The further you get from campus, the more you get for your money and the quieter the neighborhood.I currently live in a brand new duplex subdivision ($1150/month - 3 bedroom/3 bath - 1300 sq ft - enormous backyard) and it takes me about 10 minutes to drive to school. From what I know of friends' living situations, the average 2 bedroom apartment will run about $650-800/month. I would recommend living in College Station, but Bryan's utilities are cheaper.
One thing to keep in mind though: the parking/transportation system at Texas A&M is pretty horrible. As Cheryl B pointed out, it is not uncommon to drive to campus and still have to take a bus to get within walking distance of your classroom. Hopefully your husband will be provided with a parking permit that's close to where the majority of his classes/lab/office/whatever are, but he should be prepared for a walk even then. It can take a good 20 minutes at a brisk pace to walk from Lot 100 parking (where you pay $240 to park a mile away from campus, compete with hundreds of drivers for anything remotely close to the bus pick up spot, and then end up having to run to class to be on time despite leaving over half an hour before your class was supposed to start) to most places on campus. It is also not uncommon to graduate from Texas A&M with half a dozen parking tickets or more over the course of time spent at A&M. I would also not advise living on bus routes 22 or 36 if your husband should decide to use public transportation. My friend once had his fellow busmates hide behind cars and a building and then rush out when the bus stopped so that all of them could crowd on. If the bus driver thinks the bus is too full and s/he sees too many people at the stop, it is not uncommon for them to drive right on past and leave the students to wait for another bus.
Other than A&M's dismal transportation system, I absolutely love A&M. If you or anyone else has more questions, I would be more than happy to answer them! I'll be trading in my affordable living pretty soon for Washington DC and the UMD. I'll certainly miss the $450/month on rent and bills, cheap local restaurants, and $4 movie tickets!