btw, liquin is made by winsor & newton, and it slows down the drying process of oils (if that's what you want)
You can buy it most anywhere. Hobby lobby sells it
If you are avoiding canvas cuz of the cost, maybe you should use masonite panels... Just go to the hardware store and pick some up! There's 2 thicknesses at the one that i go to.... buy the thicker one... Masonite always bows towards its center of gravity, and by having the thicker panels, it slows that process down a bit...
You can use either the rough or the smooth side, just make sure you sand the smooth side with some 100 grit sandpaper..... then, slap some gesso on it, u HAVE to use gesso, or the masonite will suck up all the moisture, and the painting will flake off in about 3 months
I got a galllon of gesso for 20 bucks, the cheapest that they had...
I use masonite panels regularly, they are great for practice, and, depending on the type of paper canvas that you use... it may actually be cheaper to use masonite!
Hope this helps, glad that your having fun with oils!