Now you will need your staple gun. Start with one side then work your way around each side, pulling the canvas tight each time you staple until you get to the edges.
Now your ready to Gesso your canvas. I put gesso and a bit of water in a cup and mix it to make it more fluid. Use an old paint brush and cover the whole canvas in nice even strokes. Let it dry for about half an hour or so, then lightly sand it and apply a second coat. Make sure to get the sides too. Once it is completely dry, sand it again. Then your ready for paint!!
It is a bit more time consuming, but you save money & you can do any size you want. Hope this helps !
(For a 22x35 = $15 average cost)