What's the cheapest way to send money back home from the US?

Skip your bank's wire desk, banks bury costs in poor exchange rates plus $25–$50 fees. Dedicated remittance services (Wise, Remitly, Xoom, and similar) almost always cost less because they use the mid-market exchange rate and charge a small transparent fee. The two things to compare are the fee and the exchange-rate margin; a "zero fee" transfer with a bad rate can be pricier than a small flat fee with a fair rate. Bank-funded transfers are usually cheaper than card-funded ones, and larger transfers often have lower percentage costs. Always check the amount that will actually land in the recipient's account, not just the headline fee. For recurring transfers, lock in a service with consistently tight rates.