An old sturdy Singer (or similar that was made in the early 80's.. when they made PROPER machines) will do most fabrics obviously. I've sewn up to 2 layers of vinyl (with specific needles), and up to 3 of leather (suede) with one of my machines.. just take it slow. If you're doing a LOT of the heavier stuff, with speed and quantitity, then yes, you will need to invest at least a K in a good one that will undoubtedly take up your living room. I would highly recommend a Juki (ease of getting parts, use and reputation). There is a place in Rmd.. (can't recall the name off hand) that actually buys them from local factories that fold. They sell with warranties, etc..
