If all you need is shade, shade cloth is pretty easy to sew on and can be made quite tidy looking. But if you want dry, then something waterproof is best. Spraying with Thompson's will extend the waterproofness of fabric
tents, but regular cotton canvas
is very prone to sun rot
. However, at $25 apiece, you can buy a lot of them for what you'd pay for one made from Sunbrella or WeatherMax 80. I think the OP's tent is a nice color, too, as well as being a frugal choice.