Yes, there are multiple flights from Bangkok to Costa Rica for under ฿ 35,958. The cheapest flight booked recently is on Multiple Airlines for just ฿ 35,388, but on average you can expect to pay ฿ 47,614.
There are no direct flights from Bangkok to Costa Rica, but Cheapflights can provide you with all the information you need to find the fastest route with the fewest stops.
On average you can expect to pay ฿ 38,240 for a flight from Bangkok to Costa Rica. The cheapest flight overall is ฿ 27,549 while the most popular route, (Bangkok Suvarnabhumi - San José Juan Santamaria Intl) is currently priced at ฿ 38,505.
Departing from Bangkok to Costa Rica will take you 26h 55m.
Currently priced at ฿ 38,925, Air Canada will fly you from Bangkok to Costa Rica and back. In addition to Air Canada, many other airlines offer competitively priced options for your trip. Search Cheapflights for deals from American Airlines and United Airlines - these airlines can fly you to your destination from ฿ 39,854 and ฿ 56,904, respectively.