Use 'scrimp' when discussing efforts to reduce spending, often implying some hardship. After losing his job, he started to scrimp on luxuries.
Pro Tip 2/3
Not Miserly
'Scrimp' suggests prudent saving, not being stingy or miserly, which has a negative tone. She's not cheap; she's just scrimping for her college fund.
Pro Tip 3/3
Temporary Measure
Using 'scrimp' often refers to a temporary situation, unlike 'frugal', which implies a lifestyle. They scrimp on daily expenses to afford a summer vacation.