First shotgun purchase?

I'm looking into buying an express or wingmaster 870 used for deer, pheasant, and trap shooting. Theres 3 used expresses at the shop im looking at all at $275 with 2 being black syn and one with timber camo all mint cond. The wingmaster is a black syn stock with some use but is discounted to $250 from $300. Any suggestions? What length of barrel should i look for if im a pretty big guy (6'3) or is it just preference?