As one of its daily deals, REI-Outlet offers the ERGObaby Designer Collection Diaper Bag in Umba for $74.73 with free shipping. That's the lowest total price we could find by $12. It features canvas/leather handles, insulated bottle storage pockets, changing pad, and padded laptop compartment. Deal ends today.
There's a less expensive way, and then there's the way that works for you. The two may not be the same.