A Bushnell trophy 1.75-4X power with a circle reticle would be a great start. They run about $100 depending on which model you get. They have a wide field of view, easily acquire the target, and are quite clear for the price. Another great slug gun scope for the price is the Leupold Heavy reticle VX-1 ($180-190). Of course, with the hunting you are describing, standard iron sights would still be the best.

KEJ