J.G.
Well, I don't live in Texas (central Illinois), but we pay less than $100 a month for preschool (3 mornings a week). We chose the preschool at the park district. Very often churches will have preschools that are very reasonably priced.
There are many types, but I was looking for a play-based preschool. I feel fairly confident that I could help my kids catch up if they were lacking in reading, writing, math skills, etc. Socialization, not so much. I want them to be in an environment without me so they can learn how to respect and adult other than a relative or close friend and learn how to play with the other kids.
I think the biggest reason so many kids are going to preschool these days is that kindergarten has gotten so academic. In many school districts it is all day, and it much more of a traditional classroom setting. The kids sit a desks or tables, they are expected to know their abc's, numbers, how to write their name, etc. With "No Child Left Behind," school districts can't afford to waste that kindergarten year with shapes and colors. The kindergarten we experienced is what is happening in preschools.