What a cash buyer does pay is the same as anyone else: legal fees of $800 to $1,500 through the lawyer who closes the transaction, since title in Saskatchewan moves through Information Services Corporation rather than a third-party closing agent. Skipping a mortgage just means skipping the CMHC or Sagen insurance premium and its PST at closing.
A cash buyer also skips the lender's minimum credit score of 600 on an insured mortgage and the GDS and TDS debt ratio tests, since there is no lender qualifying the purchase, but neither of those was ever a tax in the first place.
If a tax like this exists somewhere else, it has not crossed into Saskatchewan real estate, and buyers here should not price it in. Get your hand-reviewed valuation from Joel Dyck.