I just recently paid $125 for respiratory infection treatment for a snake. That included two vet visits (one initial and one three weeks later where she was given the all clear), two bottles of antibiotics (100 ml each time - I was the one who insisted on fresh antibiotics when extending treatment for another week after the first two, this added $15), and syringes and needles for all the daily injections. Just the initial vet visit and initial bottle of antibiotics and syringes and needles was only $75. The vet specializes in exotics and only has hours once a week for a couple hours in the evening.

If you've actually confirmed $800 as the price estimate with your vet's office, finding a different vet is a much better option than putting off vet treatment.