Royal ISD (Brookshire) serves the south end, also Hempstead ISD is NW and Waller ISD in NE. Some of Waller Co is included in Katy ISD, but everthing in Katy ISD is pricey. TXLS is a good web site for land west of Houston.
Royal ISD is a small school district, about 15 min from Katy. Same problems as all districts, same good points, they have a nice campus, all schools located at one site between Brookshire and Pattison. Dependent on how far of a drive you want, Bellville has beautiful property that has not skyrocketed like Katy (at the moment).
TXLS website:
County Selection Form