FAR 2.101 states "Micro-purchase means an acquisition of supplies or services using simplified acquisition procedures, the aggregate amount of which does not exceed the micro-purchase threshold.

      Micro-purchase threshold means $10,000, except it means-

           (1) For acquisitions of construction subject to 40 U.S.C. chapter 31, subchapter IV, Wage Rate Requirements (Construction), $2,000;

           (2) For acquisitions of services subject to 41 U.S.C. chapter 67, Service Contract Labor Standards, $2,500;..."

AFI 64-117 Government Purchase Program, Attachment 1, GLOSSARY OF REFERENCES AND SUPPORTING INFORMATION states “Micro-purchase threshold” means $10,000 (10 U.S.C. 2338), except for: for acquisitions of construction subject to 40 U.S.C. chapter 31, sub- chapter IV, Wage Rate Requirements (Construction), $2,000; acquisitions of services subject to 41 U.S.C. chapter 67, Service Contract Labor Standards, $2,500;..."

AND FAR 22.1003-7 states if the contracting officer questions the applicability of the Service Contract Labor Standards statute to an acquisition, the contracting officer shall request the advice of the agency labor advisor. Unresolved questions shall be submitted in a timely manner to the Administrator, Wage and Hour Division, for determination.

I strongly recommend that you verify with your labor advisor that the SCLS exemption at  FAR 22.1003-4(d)(1)(iv) applies to your procurement.  If your purchase is exempt, then the MPT for your purchase would be $10,000 in accordance with FAR 2.101 and AFI 64-117.  I also recommend reviewing Section 7.12.16 and 7.12.19 from AFI 64-117 to determine if either of those restrictions apply to your purchase.  Finally, I strongly recommend contacting your local A/OPC , legal office, and Financial/Resource Manager prior to purchasing the service with your GPC card to verify this purchase is appropriate.