If you can deal with a fixed 4x. Natchez Shooter's Supply has a Weaver 4x32 shotgun scope on clearance for $79, MSRP was $245, actual retail was around $150 or so at most places on the net. The Optic Zone has a Weaver Shotgun 1.5-5x32 on clearance for $139 (I think), also a very good deal. For a big bore, assuming it's a 45-70 or a .450 Marlin??, I wouldn't look at anything bigger than a 1.5-5 or 1.5-6 myself. Lots of nice scopes in the low range available, 1-3, 1-4, etc.