That clock looks really nice. 1940's I think. My first thought was maybe $450 or so, but I haven't been tracking signs too much lately.
Clock is late 40's , very cool, and yours is the more rare square clock version, most are round clocks, other varieties includeing a waterfall display and another has a spinning sign in place of the clock that says "Pause" on it. These used to bring big bucks, I know I've paid more than 450 for mine several years ago, but now prices are dropping... I was going to say value of 650 or so, but it's been a while since I've bought/sold signs.. just havea bunch hanging on the walls.
Nice stuff!