Context: the black (aka "parallel") market exchange rate (USD$1 ≈ NGN800) is much higher than the #CentralBankOfNigeria rate (≈ N490) so some can profit off the difference, and authorized dollar payments are effectively subsidized by the #NigerianGovernment. I understand each bank has an allocation so the dollar spending limits per customer are to make it go round. US Dollar cards and accounts are the cumbersome alternative, but can still be rejected by a lot of online vendors at checkout.

@marqle Mostly because #Nigerian IP addresses automatically trigger their fraud checks.

Online payments are generally complicated here. The #CentralBankOfNigeria here has imposed a payment restriction of $20/month on international transactions for cards in the local currency, and occasionally there is an outright ban or the local banks limit payments themselves.