Tamarindo and Smara are two of the most popular beach areas, but there are other good choices in the area as well. This part of Costa Rica is known for large chain resorts on the beach, and the 4-star resorts can be pricey, while the more traditional 3-star hotels are still very reasonable. Costa Rica is obviously one of the hot countries in December in both temperature and popularity, so book early.
The Bali thing is also kind of a mess for those on low budgets. Kuta is a headache, and pretty much the opposite of what is so beautiful about the rest of the island, but it’s also where nearly all the really cheap beds are located. If you go a bit north in that same area into Legian and Seminyak, it’s nicer, but prices also go up. And Ubud is nice, but also more expensive for hotels and such. I’ll probably rent a place in Seminyak for a few weeks, which won’t be cheap.
Trekking in Nepal during peak season might not sound like the most sensible choice for penny-pinching backpackers. But you can still enjoy the ideal weather without spending a fortune on in-demand hotels and expensive permits if you're happy to swap big-name trails, like Everest Base Camp and the Annapurna Circuit, for quieter treks to Kanchenjunga Base Camp and around the Langtang Valley. Idyllic conditions (dry but not witheringly hot) are also on offer in Rajasthan, one of India’s most vibrant and varied states. Chug between notable, attraction-rich cities like Jaipur, Jodhpur and Udaipur on an atmospheric and wallet-friendly Indian train, snacking on spicy pakoras and sipping sugary chai en route.