Translation:I would not have been able to pay for that apartment.
if we drop 'teria', then we have eu nao podido pagar por aquele apartamento. This would be rendered as 'I couldn't have paid for that apartment.' Since 'poder', the verb, is similar to 'conseguir', in that it means 'to be able to', at least in this sentence it does. The question is why have the much more complicated construction? I guess it's practice for us with complex sentences.