I bought this simply looking bag organizer at Penneys (Ireland's Primark) for €4. It has 14 pockets to put all my stuffs that I usually bring when going out. The middle compartment can fit an ipad, so that's basically it's length. Transferring it from one bag to another is easy because of the handle. And I don't need to remove every bits inside.
It is one thing I never regret buying. It made my life easier. :)