$400 or less would be a good deal, but not nuts. Greatest deal/best price was $300 (on sale and then a discount code at LB). These prices were for a new MAM. If we're talking used, it would depend on how badly I wanted it.
I got my black MAB for $200! That was a once in a lifetime steal, IMO. I think $300 is a can't pass it up price and anything under $400 is a good deal.