International remittance - atlantic money does $3 or something flat. By the time you get your cash into a crypto exchange and out, you are hosed for more than $3. If you can be bothered to open an account with someone like Interactive Brokers (yes, a traditional online stock brokerage) you can do it for about zero - you get wholesale FX prices and you can deposit/withdraw money from various accounts as long as you have all the paper work in place - annoying, but doable.

Again, a couple entries into relational databases, which is the true underlying cost structure of "traditional finance" is really hard to beat.