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?
Casio F91 I paid $9 for.