As far as I know, a fecal isn't expensive...
How much are we talking about? I can't afford much.
At my clinic we charge $15 for a fecal, and we do both a floatation and smear, but if parasites are found, we have to do an exam before prescribing medication. Exam fee I think is about $50 for exotics. Ideally, the best stool sample is directly out of the snake at the visit, but a very fresh one (as in, checked within a couple hours after they poo) is ok too.