Costa Rica's residency is genuinely accessible and comes with one obligation nobody budgets for, plus a wet season that closes half the coast.
Mexico is cheap in pesos and increasingly not in dollars, and the cities with the largest expat populations are where that gap has closed most.
Mexican residency is straightforward and must be started at a consulate abroad, which is the step that catches people who are already in the country.
Panama uses the US dollar, offers one of the easiest residency routes in the Americas, and taxes territorially — which is an unusual combination.