Well fecals will run you anywhere from $15-$35 if a vet will do them local, sometimes you have to get them shipped overnight if you don't have a local vet that will do it. Then you will be sending out another fecal in 3 weeks because they may or may not be detected the first time around. Generally a record of 3 clean fecals means you have a healthy animal so that is going to range from $45-$105 for a local vet or about $69-$126 to ship them out.

I have no idea what meds would cost.

OR you could get a vet to do a autopsy on the mice to see if they have parasites. I hear that's expensive too.