Are you looking to paint it as well or just drape camo over it? You can get gallon buckets of dead dull grass, marsh grass, etc. Check the cans as most of the time the paint is hard in the bottom or so it seems. Pick up a gravity paint sprayer from Harbour Freight. $20-30. You can buy a roll of burlap or go to Goodwill, Salvation Army etc and see what types of bulk material they have and get fabric dye or buy the pre-cut camo sheets. They are usually 5' x 20'. There are lots of options. From inexpensive to more elaborate. There also have been several Avery pop up blinds on craigslist. Ranging from $250-$450. That may be an easy option.
First boat blind was PVC for a 12'. Then next one was aluminum and welded with green chicken wire brushed out. I now have a Avery Pop up blind. There are a ton to look at on the internet as well.