I was introduced to the 1940's style Military Watch collaboration made by J. Crew and Timex perusing the pages of GQ. The watch which comes with a black strap retails for $150 at J. Crew and additional watch straps are $20 or two for $30. This watch opened my eyes to the interchangeable watch strap and as a buy low value shopper this appealed to me. Whether you want to coordinate or get board easy, it almost like getting a new watch or transforming an old watch for $20 or less.
Ok, that's enough talk, $150 is not bad because of the options this watch gives you but here's where/how you can pay even less.
The cheapest way would be to remove the the strap from a watch that you currently own and just buy the strap(s). The straps usually come in 16mm, 18mm, and 20mm widths (with wider or narrower options available) and the length is usually 9 to 12'' so make sure to buy the right sized strap for your watch.
Or you can buy this
Citizen Eco-Drive
watch for $80 or for even less
Timex
watch for $26! Also you can find Watch Straps on eBay or at
Central Watch on sale 5 for $30.
and the Explorer II
I found out about TungchoyWatch.com on eBay while looking for an even cheaper alternative to the J.Crew straps and I've bought three watch straps from him (shown below) since. You can get them in a solid color for about $10 and striped from $18. Check out my Watch Strap Guide (here)!
The cheapest way would be to remove the the strap from a watch that you currently own and just buy the strap(s). The straps usually come in 16mm, 18mm, and 20mm widths (with wider or narrower options available) and the length is usually 9 to 12'' so make sure to buy the right sized strap for your watch. 
