This has to do with rewards for Christian service in the Day of the Lord. There is nothing about Purgatory in there.
Jesus talks about not getting out of prison until paying the last penny: Matthew 5:26/ Matthew 18:34-35/ Luke 12:59
These are a parable that Jesus is using to teach a point. If one is going to say that this prison is Purgatory, then by doing what he says, one can stay out of it.
But think about the illustration: How does one earn money in prison to pay someone back to get out of it. Do you remember debtors prisons? People were thrown in prison until they paid their debt, but they could never pay their debt because they were in prison --- so they never got out.
I hate to muddy things up again, but some people have family and friends, who help them out when they're in trouble.