I had the exact same problem when i got my first cruiser in '05, a speedmaster. The leg thing that is. They would get tired and i felt like i was expending a lot of energy keeping them in with my leg muscles. It was torture. It did stop eventually and now i have no issues with that, but i won't lie to you, it took quite a while. I'd say tolerable by several months and took probably a year or more to be completely over it. YMMV tho. I really can't see it being as big a pain as it is to you now for too long, as you become less conscious of it after a time even before it goes away. But i had that bad, so i know exactly what you mean. Worth ever moment of it tho, especially the Tbird. You will get that at first with any cruiser if you like me are prone to it. Doesn't bother some.
As for cost, you should be able to get a pretty good discount. I would say an out the door total cost of MSRP plus $700 at least. Thats what you can get in my area anyways, tho there is completion with 5 or 6 dealers within a 80 mile diameter. But you have to know how to play them and not let them screw with you.