On the second Saturday of the month at Tractor Supply in Denton (Loop 288) there is a vet who does them. Their prices are pretty good. We've gone there several times. They also have heartworm preventative (and tests if you've not gotten the preventative there before) and the flea control stuff too at good prices. Also, if you aren't squeemish you can get the Parvo and one of the others (I'll ask my DH if you're interested) at Tractor Supply and do it yourself. Rabies must come from a vet though.
Also, on Tuesdays from 4-7 pm and Saturdays from 9-12 pm at the Albertsons (look for a small RV in the parking lot) in Denton (University Blvd/380) is the Mobile Vetrinary Services (817-925-0339). Their prices are also good. Rabies vacc: $7.50, DHAP: $14.50, Parvo: $11.50.
Hope that helps.