I have an old plastic one similar to this

http://www.mec.ca/AST/ShopMEC/Cyclin...sure-gauge.jsp

mine is very light, is probably similar in build quality to this and still works after having it I dunno, 15 yrs or more of being wrapped up in a cloth along with my other tools I have with me. That said, since getting a small pump with built in gauge, I tend not to take it with me anymore (and I have a floor pump with an easy toread gauge that I use at home)

you should be able to find a gauge like the one I put up, for somewhere around 15 bucks that will last a long time and doesnt weigh as much as a metal one.