What's a word that means a person tries to find an easier, cheaper way? [duplicate]

Solution 1:

She is being a niggard.

Example:

A niggardly tip to a waiter.

It means that the tip was ungenerous or scanty.

Solution 2:

I would say that your mother is economical:

marked by careful, efficient, and prudent use of resources : an economical shopper

[Merriam-Webster Dictionary]

Resources could be extended to include things like time and money