I have only recently been trying the gesso paints, and they are much more liquidly than tube acrylic. Most of the canvases i buy aren't expensive, mostly as I am still learning and don't have space for huge bits of art.
I have bought some canvases and they are a bit powdery, so I will probably gesso them first. I tried the first time a black canvas with gesso on then the liquid clear and oils on top, I love the mix of these 2, and the technique, it's very satisfying. I honestly don't think the effect would be the same had I used standard tube acrylic though.