Look at watches around $60 or less. One of the top recommendations I keep seeing is the Casio G-Shock line. Here's an example:

Casio Men's 'G-Shock' Quartz Resin Sport Watch https://www.amazon.com/dp/B004IYZ17Q/ref=cm_sw_r_u_apa_i_pclKFb56WCQMY?_encoding=UTF8&psc=1

I always heard that a watch should be rated to 200m to be used for diving. Not that you'll go to 200m, but that's what I always was taught. I'd look hard for a G-shock. The simpler old-school models can be around $40-50 on sale, and they're damn near indestructible.

This one is $38 on Amazon: http://www.amazon.com/Casio-DW9052-1BCG-G-Shock-Multi-Function-Digital/dp/B004IYZ17Q/ref=sr_fsl_cat_softlines_brand_0_1?s=apparel&ie=UTF8&qid=1435050769&sr=1-1-fed_softlines_strip_1&keywords=g-shock