That is true, HBE. He was calculating how many years he would have to work in order just to live there. True, Columbo was poor. And in Negative Reaction, when the nun says to him "Oh that coat." More proof, poor guy couldn't even afford a new raincoat.
Also in Identity Crisis at the gas pump...counting out change..
And in Publish or Perish where he is asked to pay 6 dollars for a bowl of chili and then the waiter amends the check because he forgot to add the 75 cents for the ice tea..(love that scene!)
But I get the feeling he wouldn't have it any other way. His social-status separation from his suspects is one of the things which allows him to get (if not keep) them off-guard. Make sense?
And his shoes in "Exercise in Fatality." When he and Janus are talking and Janus asks him if he wants a shoe lace. I think a complete new pair of shoes would be the call.