I was watching a documentary about Dale Chihuly (a glass artist) who used Acrylics in squeeze bottles (similar to ketchup dispensers) to do his preliminary sketch paintings with prior to doing it in glass.
The style was rather reminiscent of Pollack, very loose and free.
The Acrylics in tubes are way too thick. The company at the link below makes Acrylic in all different consistencies and many art supply places carry them in larger sizes which are far less expensive than tubes.
Another possibility is craft Acrylics by companies like Plaid which come in smaller sizes but can often be found on sale for around $1 per bottle.
Some of the stores where I have purchased both of these different brands of Acrylic are Michaels, A.C. Moore, Dick Blick and Pearl Paints.
www.goldenpaints.com
www.acmoore.com
www.pearlpaint.com
www.plaidonline.com
www.dickblick.com
Both A.C. Moore and Pearl Paints carry canvas by the yard and pre-cut, snap-together wood frames in various sizes you can use to custom make your own.
Another alternative (although heavier) would be Masonite which comes in large sizes.
I’ve also seen people make custom painted area rugs in fairly large sizes by buying cheap linoleum flooring on sale and painting on the back (unpatterned) side.