Honestly... In all my festivals and in all my searches there isn't a cheap and quality canopy. Coleman and Ozark Trail make cheap ones and offer straight leg options, but the first nasty rain or big gust of wind and it's got a good chance of getting totally trashed.

Best one that I've found and researched was this one. Granted, it's not the cheapest but it's worth it if you camp and festival a lot and plan on doing it for years. Otherwise there's a good chance after a couple years or even just one festival that your $50 on the cheap one was thrown away.

All this said, if money is tight, check out Aldis or Big Lots. Sometimes they have some really cheap ones that might make it through at least one festival. Maybe more.