In areas where bear bags are required, rentals are often available.  Where precisely are you going?  It would be worthwhile to check out requirements beforehand.  Some places get very serious about bear bags and levy significant fines if regs are not followed.

just as important as a suitable bear bag is a scrupulously clean camp, with all odorous items tucked away in a properly secured bear bag.

I am not an REI employee.... 

Superusers do not speak on behalf of REI and may have received
one or more gifts or other benefits from the co-op.