I have a Stone Glacier for myself with load shelf and I have an old aluminum pack frame with bag/pack mounted on it that my friend uses when I hunt for Elk. He carries it with some some day items and to pack Elk out. It has finally met its demise and want to replace bag only. Where do I find one that doesn't break the bank and but will work still use existing frame? Bought at Gander Mtn. 10-12 yrs ago. Thanks