Vet recommendations?

I need to get my dog flea prescription medication (not trying to deal with the over the counter stuff, flea collars, flea bath, etc.) and was wondering if anyone had any recommendations for a veternarian in the Greater Houston area with regards to lowest price. If our issue was something more serious, I would be considering price much less highly, but the fact is my healthy German Shepherd might be driving my household (and definitely herself) slowly into madness with the itching. She used to be on Triflexis (I think that was what its called), tolerated it very well and needs a rx to get it again. The economy being what it is, I've been maintaining her health thru flea shampoo and sheer will power- but its getting hot and the fleas are officially beyond what any creature should have to deal with. I have some money for the vet but you know, I like affording the gas and food and such to live off of too…. call me nuts. Please any recommendations would be rad, I'll drive anywhere within the beltway or even hwy 99, and if you had specific prices/services offered (or required) to get the damn rx, please include them. Lucille and I thank you kindly!