Casio M5610U with a metal mod I picked up for $99 and I love it! Pick up and go with never a care for durability or accuracy. World time across 5 presets, that you can swap back and forth with your home time at a press of buttons, solar powered, and radio receiving for auto updating of time and date.
What's your cheapest watch in your collection?
This beast: https://www.casio.com/us/watches/casio/product.MDV-106-1AV/ Has been in many dives, beaches, boats, hiking trips, whatever; for over 10 years.
https://preview.redd.it/m4voh2v9d6wb1.png?width=790&format=png&auto=webp&s=648b511fdbfdfe00493b6d3ca34436cd742d6ced
Does it have a quick strap for changing?
No. The strap is the weak point, it's not very durable rubber especially with exposure to salt water. I'm on my third strap.