As this article shows, you can make a big change in your place with a small amount of paint. Minimally Designed Apartment With Punches of Color (Design Milk).
Case in point, this door and the fixture above it:
Depending on the object you paint, you could get a big change with a small can of paint. Low cost, low effort, big difference. Well worth it.
See the link to Design Milk (above) for more great examples.