Hi xPhilx, Welcome to A.O.
Getting an A4000 can be tough as most owners dont want to sell them. Ebay is a good place to find them but of course as you know they tend to go for high prices although the one you mentioned went below what most go for.
Rairly you will find them at garage sales and flee markets and most of the time the sellers dont have a clue how much they are worth.
I hope you find one for a good price. There is always a possibility someone on here will have one that they will sell.