While it is terrible buying this animal is not the answer, soon as you will buy it they will have another one to replace him and if it eats it eats and if it doesn't it will be the same story all over again and what are you gonna do next, buy all their non feeder.
Problem with petco and petsmart is that they are rarely allowed (per their corporate policy) to feed live and if the animal does not take f/t they either watch the animal die or force feed or assist feed it (granted someone knows how to do it)
This animal should be surrender and rescued not sold for a profit, ultimately paying to rescue an animal is only encouraging this type of things to continue.
Sometimes you can't save them all.