The difference between the "express" model and a "regular" 870 is the "Express" is a rougher finished gun, barrel and receiver as well other differences. The express will sell for about $350 - $400 range brand new with both barrels and a scope, a regular 870 would be aroud $900 - $1000 by now would be my guess, yes only a guess.
My buddy just bought one ( Express ) @ Dicks Sporting goods and it was a green composite stock and for-end with two barrels, cantilever scope mount attached to barrel with picatinny rail, scope, bird barrel w/ interchangeable chokes & a vented rib...... all for about $400
Check out Remington's site for their description
Hope this helps