Recommendations for a heavy duty sewing machine for webbing?

I want to do some projects for camping backpacks, bike bags, and other things of that nature. I'm looking for a machine that can handle thick and heavy materials like 3 layers of webbing, and can do a basic zigzag stitch. I don't have the budget for a sailrite. Is there a commonly available machine (antiques are okay too) that can handle this that doesn't cost an arm and a leg?