Up here in MN, its a bit different again. I have a brother and my mom that are both certified testors. You pay $80 to take the course and sit through an all day seminar with the state vets. Then one of the district vets actually comes to your farm and watches you actually test a certain percentage of the birds. The antigen and supplies are provided for free. You just have to stock up int he fall because it will freeze enroute otherwise. It is up to the individual testors what they want to charge. If its people we know, we usually have them meet us somewhere and do it for free. If its someone we have no idea on and they live 40-60 miles away, its either $0.50 a bird or enough to cover gas if its only a few birds. The people at the swaps charge anywhere from $0.50-2.00 per bird and it depends if they have to supply the bands too.
Testing on turkeys for MG/MS is a bit different. Its not done on the platelet. You have to draw a 10 ml vial of blood on each bird and send it in. You first get the paperwork back on them about 10 days later. If you do it in the winter and the vials even partially freeze enroute, you will get false positives showing up.
Now for an exhibitor's requirement on paperwork up here.... What the state wants and what is actually in writing so far are 2 different things. The state wants ALL birds to be tested within 90 days of the show/swap/etc even if they are NPIP. Technically in the rules, it says in-state waterfowl are exempt from testing for exhibition purposes. It also states that if they are from an NPIP source, they can just get by with that documentation too. Now if you are coming in from out of state for a show, you have to follow the import laws first of all. This applies to waterfowl as well. All adult birds have to have PT testing within 30 days and a current CVI- certificate of veterinary inspection. Hatching eggs and chicks need a permit from the state to be shipped in.