Does Mrs. Crater have any moral justification for her actions in the short story, "The Life You Save May Be Your Own?"

There is a redeeming feature in Mrs Crater's actions, yes. One could suggest that Mrs Crater's concern for Lucynell's care after she has died, for she is old, may be the one redeeming feature she possesses. She clearly dotes on her daughter and finding someone to look after her once she is gone, is a noble ideal. There are however, a number of other factors which one should also consider before making a final judgment about her.

Mrs Crater also comes across as a self-serving individual who uses her innocent daughter as a bargaining tool for the following reasons:

Firstly, it is clear that Mrs Crater is lonely. She is desperate for company, someone she can talk to, since her daughter, Lucynell, is hearing-impaired and has not spoken a word in her life. Mrs Crater can therefore not conduct a conversation with her. She has been living alone with Lucynell for fifteen years since her husband died. 

Secondly, she needs a handyman who would fix everything on the farm that needs repair and who would run the place for her. She is old and tired and lacks the drive or skill to do so herself. In addition to this, she needs someone to take care of Lucynell and getting her married would save her the trouble of having to take care of her. 

Also, hooking someone by having him marry her daughter, would provide cheap labour, for it is clear that she is quite stingy.

Mr Shiftlet's arrival provides Mrs Crater with the ideal opportunity to obtain all that she wants. She exploits Lucynell's innocence to lure Mr Shiftlet and she admirably succeeds in this venture. Lucynell has become a carrot which she dangles in front of Mr Shiftlet and he seemingly takes the bait. He marries Lucynell at her suggestion and she is obviously highly pleased with herself at having coerced him into this act.  

However, it is ironic that Mrs Crater does not realise that Mr Shiftlet allows himself to be so easily manipulated. He also has an ulterior motive and slyly gives in to Mrs Crater's suggestions. He first impresses her with his skills by fixing various parts of the house and doing the required chores on the farm, but his main interest is the car, which hasn't run for fifteen years. Shiftlet has never owned a vehicle in his life and he has seen through Mrs Crater's scheme and uses her gullibility to get what he wants. 

In the final analysis, Mrs Crater's plan backfires terribly, for Shiftlet abandons Lucynell and steals the car.