I have no pricing info for you, but i have interacted with two different systems.
Our plant uses Swisslog, and i got to see a presentation on MiR after the plant was launch.
Software and capability wise, i would choose MiR any day. They are smarter, and more capable of detecting obstacles and planning accordingly. Swisslog are either very incapable, or we cheaped out at the project level and chose not to get products that suited our needs.
That being said, it is hard to beat Swisslog for capacity. Ours lift and move 2000+ lbs over and over all day every day, never had a failure in the lift.
The problems are typically a weak signal connection (if they drive such that an I-Beam passes between the AGV and the wifi router, it stops dead) and poor view range (a triangle from about 6 inches from the floor, out and down to see about 2-3 feet ahead, which has led the the AGV's seeing BETWEEN the wheels of a forklift and hitting it).
If you are in the midwest or new England area, contact Neff about MiR (i am sure there are distributors and integrators in other regions, they are just the one i am familiar with).
Swisslog (i believe) is the parent of Kuka robotics, but i may be mis-remembering.
Shop around for some AGV options that meet all of your technical requirements before you start looking too hard at price, or you will end up with 25%-50% of them in a roomba graveyard.