what are you looking to spend? What sort of rifle - spring, gas, PCP?
Most of those Walthers are Chinese. Gamos are generally not well regarded but are popular none the less despite their many problems. If you don't mind spending a few bucks look at the R-9 from Beeman for a good spring rifle. Other options are the Benjamin Discovery from Crosman, and excellent entry level precharge rifle, or any of the Benjamin/Sheridan pump rifles in .20 or .22 cal. RWS/Diana rifles such as the model 34, 48, 52 or 54 are also good choices with a fairly wide price range. Compasseco has a good selection, so does PyramidAir.