i have seen ( and used ) game bags of all stripes in the field, from used pillow cases to black garbage bags. some folks like heavy canvas while others like the light weight and inexpensive "cheese cloth" type.
my experience is with transport, and not just protection and so personally i like the canvas quarter bags. these bags reduce the size of the load to a manageable weight, and are strong enough to support a load hanging to cool. they are sold in many stores under the name "alaska" or "wyoming" even "montana"........it seems adding a colorful title improves the sale numbers.