The plaintiff in any judgment recovered on a tax claim, in which proceeding the certificate provided for in section one of this act¹ has been filed, may, with consent, filed of record in such proceedings, of the holder or holders of municipal claims, if there be any against the property involved, fix, as the upset price to be realized at the sheriff's sale under such judgment, the market value of the property as set forth in the said certificate, or such higher upset price, not exceeding the total amount of delinquent taxes due, as it may determine. In such cases, no sale shall be made except for a sum not less than the upset price so fixed, and the plaintiff may purchase the property at such sale for that sum, if no higher price is bid therefor.