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?
Vintage Vostok Amphibia. Only cheap vintage watch that’s never given me grief. Probably G-Shock DW5600 after that.