Have you ever tried resawing 2x4's?? If you like woodworking and are comfortable with a table saw, resawing 2x4's is a great way to save money on a project. I've cut 2x4's into 2x2's and 1x2's on this little DIY Side Table project. I've also used resawing just to trim the rounded edges off of 2x4's to give them a nicer, cleaner edge. You can see me resawing for this project in the video.
For this table top, I spent less than $10 on the paint and wood.