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?
Cheapest that I bought new? $11 Walmart clearance Casio Duro
Cheapest overall? $2 Timex Explorer from a flea market
By contrast, my most expensive watch is a Marathon GSAR (About $1600)