That's the real gospel you have neither heard nor understood..More made up conjecture. More imaginings.
There were no free samples given in the parable. The parable isn't about salvation. Not in the slightest. It isn't about grace.
They all had oil, some had a lamp full, some had a lamp full and an extra flask. Everybody's lamp went out in the story, because they became drowsy and went to sleep. When they were awakened with a shout, the five who had an extra flask were able to replenish their lamps, while those with no extra oil were told to go to market and buy some.
You think the oil is grace? You think the five wise ones bought grace? --by paying all they have to obtain it?
That's a new gospel, friend.
Let us therefore come boldly unto the throne of grace, that we may obtain mercy, and find grace to help in time of need. Heb. 4:16
The cost to approach that throne of grace is all we have and are. We are to BUY eye salve so that we might see. But spiritual things are foolishness to the masses. How they be understood?