You need to bring in the feces. I don't know of a vet that can loop a snake and get a sample like they do with dogs. Next time your guy leaves a present for you bag it up in a ziplock and place it in the fridge. Do it as soon as you see the poo. Then make your appointment for that day or the next. The poo needs to be fresh and refridgerating it will keep any eggs in the poo from hatching before it is examined.

My last vet bill for a herp was for a gecko with a prolapsed hemipene and the total cost for meds, removal of the hemipene and vist was $94.

You should call and ask their prices, you will get charged for the initial exam/visit $35-$60 (average), the fecal $10-$20 (average) and some sort of wormer if needed $5-$25 (depending on meds). So I would estimate $50-$105 for the whole thing based on my limited experience with different vets.

Hope this helps, keep us updated.