What is the cost of Unmortgaging Park Lane / Park Place in Monopoly?
You round up. So the unmortgage cost of Park Place is $193.

The rules for the electronic banking version of monopoly have this specifically listed in the mortgage rules.

page 12:


  Repaying a mortgage
  You must pay the original mortgage amount plus 10% interest (rounded up to the nearest 10,000). Once the mortgage is repaid, turn the Title Deed card faceup.


emphasis mine. 

In this version you start with $15Million instead of the normal $1500, so the nearest $10,000 is equivalent to $1 in other versions.