i might be completely wrong but i think there is a difference between a rubber pleco and a rubber LIP pleco. rubber pleco is another common name for what i believe is the chubby pleco which grow to 8"+ i think while rubber lip only gets to 5"
actually i just confirmed this. If the op meant that rubber pleco for $40 was too expensive becuase petsmart has them for less...petsmart has rubber LIP pleco which is a completely different pleco from a rubber pleco which is what the website is selling for $40.