M.L.
I worked at a vet and can tell you taht the prices vary graetly according to where you go. I've seen full vaccs+fecal+heatworm testing run upwords $200-300. If you go low cost, it can all run around $70, so it's worth it to call around to see who offers low cost clinics.
Heartworm tests usually run from around $20-$40. Also, she will need heartworm meds. They run more expensive according to your pets weight. But they are essential, especially for an outdoor dog in Texas. I've seen many dogs dog of heartworm.
I would go ahead and shave her now. You will have to get the vaccs when you drop her off at the vet, so if the vet does grooming, you can get it all done at the same time. Or, there are many mobile groomers that come to your home and in that case, they don't typically require all shots.
We shave our dog ourselves. She's a lab/border collie mix and it takes about an hour. If your dog is calm, it shouldn't be a problem. Pet Smart has good sheers.
Be sure you have plenty of fresh water for her outside and get her shaved asap.