How did we ever cut up our jeans without a how-to guide back before the internetz? American Eagle teaches us how to turn our jeans into shorts! I would buy jeans from Goodwill and give it a try. That'd give me tons of cheap summer shorts
Add fabric to upcycle shorts. Place fabric over shorts, trace outline of pocket + or extra, cut, then fold or place in pocket and sew (you fold that extra fabric so it looks like a professional seam). Then add fabric to the bottom and your done!