Sellers with high postage

I see people selling small items for say $30 with a large postage cost of like $500 (item located locally) which I think should  not be allowed , its almost ripping people off, I know you dont have to buy it but even if its worth $500+ if it was faulty then they only have to say they have no more stock and only have to back the $30 and keep the $500 postage as they dont have to reimbust the postage?