Yuma's most distinctive shopping is in Los Algodones, Mexico — a 10-minute drive to the border crossing — where a dense strip of pharmacies, dentists, opticians, and souvenir stalls operates specifically for American visitors. The peso goes a long way for pharmaceuticals and eyeglasses.
Back in Yuma, the historic downtown area along Main Street has a handful of antique shops. The Foothills area east of town has big-box retail if you need it.