I can't afford gesso, but have a lot of white house latex, would that work?
Honestly, I can't say yes or no to that...I would probably try it, because in my experience, acrylics can go over a lot of materials. The problem is that I don't know if the housepaint will stick to the painting that's already on the canvas. Without actually seeing/feeling what's on the canvas now, I can't really say anything more. But please remember that I'm pretty destructive when it comes to being creative, so I don't feel too bad when taking huge risks. Do what you think is best for you! Good luck, and I hope it works out wonderfully for you