frugal
Careful with money and things so they are not wasted.
Frugal means careful about spending money or using resources, avoiding waste without being stingy. A frugal person thinks before buying something: Do I really need this? Can I find it for less? Will it last?
Being frugal is different from being cheap. Someone who's cheap might refuse to chip in for a group gift or buy low-quality items that break quickly. A frugal person spends wisely: they might save up for something that costs more but lasts longer, or shop at a thrift store to find the same quality at a better price. They pack lunches instead of buying them every day, not because they can't afford it, but because they'd rather save that money for something more important.
Frugal people often find creative ways to stretch their resources. They might repair a torn backpack instead of immediately buying a new one, or swap books with friends instead of buying every new title.