I just bought a plank of wood at Home Depot, stained it 3 times, and then got out my trusty ruler and pencil and started marking off lines... (3 inches for the numbers, 2 inches for the quarters, and 1 inch for the rest)... I then went over all my pencil markings with my newly purchased Sharpie paint pen.
Next step was putting on the numbers. Amy printed off numbers for me, I rubbed the back with pencil, and then just traced them onto the board with a pencil so that it left an outline on my new 'ruler'. My Sharpie paint pen was utilized again. When all was said and done, I just put a clear finish on it. Total cost of all products, stains, and finish... less than $20. Love that.
The hardest part was hanging it on the wall... there may be a few holes that are conveniently covered up by our new growth chart, maybe :-)