Prepaid vanilla mastercard. Be sure to register your prepaid card at the website listed behind card;

1: In SE account man. select add crysta, 2 000, then choose UltimatePay. (the other payment methods never worked for my prepaids)
2: For my prepaid mastercard, i selected mastercard in UltimatePay.
3: Add card info, dont forget security number behind.
4: For name, type Vanilla, but real address and postal code.
5: Pay, (ultimatepay has a 10% markup in my area, so 20$ is 22$)
6: Use crysta to pay in mogstation. (go to Proceed to Payment, red tab, recurring sub setup.)
7: phew! hope it works for yall.