économiser in English:

Their reduced income forced them to economise.

It's a tight budget, so we're going to have to economise if we are going to stay within it and not to overspend

Remember to save the file frequently.

Every week I try to save some money for my holiday.

1. Save the file on the desktop. / 2. I'm saving for a new car. / 3. Thank you for saving my cat! / 4. Remember to save the file frequently.