If your smaller projects call for clear pine without any knots, you can save money by buying a lesser grade, then cutting out what you need from the clear areas between the knots. Also, when buying wood, remember that face grain is not critical for structural parts which won't show. You can likewise save on lumber costs if you can use shorter or narrower boards, or if you only need one good side of lumber for your project.
When sawing wood, take time to consider which side of the material to having facing up. Keep the good side up when you are using hand saws, scroll saws, bandsaws, tablesaws and radial-arm saws. Keep the good side down when using a portable circular saws or sabersaws. The principle is to have the tooth of the blade first break through the rough side of the board or panel.