Update: The blue backpack is now $38, but the orange is still $32.
AmazonBasics makes an oddly-specific backpack designed for ourdoor photography enthusiasts, and it’s just $32 today in both blue and orange. The pack is lightweight, has a configurable camera compartment that can hold lenses, flashes, and other accessories, plus a main compartment big enough for a laptop, and straps to hold a tripod.
If I could be so bold, I think you should take it on your trip to Costa Rica.