Nice to see more peeps reppin' CA/SA. I always hear about Asia (hitting up later this year)
I'm just getting started on my journey and have only spent a little bit if of time in the countries below with Guatemala being the longest.
Costa - Expensive (as others have metioned) but if you want some of the first world luxuries without having to travel back to the states, it's a good spot to kick it for a few weeks. Manuel Antonio is arguablable one of the most beautiful places on earth.
Nica - Very beautiful country. Lakes, volcanos, beaches and extremely affordable. Spent some time in SJDS, Granada, Ometempe, Leon and Maltagalpa. Wifi can be a problem in remote places but I was able to get a decent signal in places I wouldn't expect - like Altagracia.
Guate - Takes the cake of all three in terms of affrodablity and diversity. I lived in Antigua for a month and was able to find a 1BR/BA apartment on AirBnB for $350US/mo. You can find cheaper accomidations in San Pedro. Food and booze are dirt cheap and there's plently of cafes in Antigua. A new co-working space just opened as well. Tikal (Mayan Ruins) and Sumac Champey make for kick-ass weekend trips.