Go with the tied and true 870 and rule the world, and not the new goofy looking 870 (the one that looks like this Tristar). There is a reason 870's have been around so long and sold so many.
WWTNSTKBLD (What Would The Navy SEALs That Killed Bin Laden Do)
A good solid used 870 is about that much. sure it does not have a tac tube, but the same gun (with ten million more around for parts and support) is available new for about 50 dollars more.