If you pay for the $85 CLEP ticket on your own, without using their voucher, Modern States won't reimburse you. Someone on Reddit mentioned trying that, and Modern States wouldn't give them a reimbursement. They only reimburse for the proctor/testing fee. The testing center that you will go to take the CLEP test is the place that will charge you that proctor/testing fee (usually between $20 - $40). They'll give you a receipt after you pay for the proctor/testing fee, and then you have to scan/take photo of the receipt and sent it to Modern States requesting a reimbursement here : https://modernstates.org/test-center-reimbursement/
P.S. Upload your test score paper, along with the proctor receipt, because they ask for the test score too.
P.S. Upload your test score paper, along with the proctor receipt, because they ask for the test score too.