In my area (WA State) one boarding facilities with an indoor arena and a gated entrance charges about $450 a month. It rains here a lot (maybe not such a problem in TX!) The arena is average sized but covered, and the facility is located on 15 acres, fenced and crossed fenced, so that if a boarder felt strongly about keeping their horse next to a horse but not in the same turn out, this can happen. Separate lockers for boarder's tack with saddle racks, indoor wash area, out door round pen and outdoor arena. I like watering my horses from buckets as the water intake can be monitored better. The more fly control, the better, I think. The horses, when I boarded, were fed 3x a day: breakfast hay and grain (or complete feed), noon local hay IF indoors and not in field, evening hay & grain/complete feed. Supplements were bagged by the Owner and labeled with horses name with bins for each day, both a.m. And p.m. This way amount of any meds or vits/herbs to be fed were controled by the Owner and known by the feed person. Hay and grain/complete feed time was always separated by an hour or so....
My barn has a paddock off of each stall and I love this. We just brought our horses home a couple of years ago but boarded before that without our horses having paddocks. Not something I liked. But paddock footing is important.
If boarding fees range from $300 to $800 in your area, you can probably aim for the middle, say $450 to $550 while you get your name out there.
I hope that this helps & good luck!