Every provider quotes a different rate and a different fee. The gap between the best and worst on the same $500 transfer is often more than a bag of rice. Compare them side by side.
This is what the gap between the best and worst provider on this transfer could actually buy in Nigeria right now.
Every provider sets its own naira exchange rate, usually a little below the real mid-market rate. That markup is where most of them quietly make their money — not the fee.
Some charge a flat fee, some a percentage, some both. A $0 fee with a bad rate can cost you more than a $4 fee with a good one.
Bank transfer, mobile wallet, or cash pickup — faster and more convenient options sometimes carry the worst rates. Worth checking before you assume "instant" is free.