Alternatives to free standing/perm, attchd shade structure?

It sounds like you are looking for something inexpensive, waterproof, lightweight, and easy to set up. We have a simple 10'x10' canopy that we bought at Rite-Aid many years ago, but they still sell them for around $30 I think. It has a frame of aluminum poles and a plastic cover. When stored, it fits in a bag a little bigger than a folding camp chair, it weighs very little, and sets up in just a few minutes. You can stake it down in bad weather and it is 100% waterproof.