Sportsmans Guide has a portable beach umbrella for 14.97 + shipping (5.99 if you only order the umbrella). I shopped around for it and this is by far the best price (Sierra TP has it for 40, i've seen it for 70-80). I plan on using it at the beach AND w/my POS patio table.
Specs:
Fully adjustable tilt, 6'6"diam. Umbrella
Folds down to 30"
Durable polyester fabric resists fading from sun with SPF 50
Lightweight, rust-resistant aluminum frame