We use PVC fabric and glue our top tube bags. To make them as waterproof as possible we use YKK Aqua guard zipper.
Those bags are custom so you can choose any form and capacity for your top tube bag

Prices depend on sizes of the bag, and numbers of additional options, like pockets, separations, etc

For Half-tube bag, prices start from 60€
For a Full-tube bag, prices start from 110€

Bag like on the video below costs 130. Front part of this bag costs 70€.