I pay what it takes to get what I want. I paid $250 for one, but I was after the cabinet and didn't really care that it came with a 401a with all the attachments. I didn't even really want the machine as I already had a couple of them.
I also paid $100 for one in a decent cabinet with all the attachments - and I was after the machine with that one, the cabinet was too "new" for what I collect. Though I'm actually using it as it's got a lot of storage.
And then DH picked one up for $50 in a small cabinet.
We only paid $25 for the 401g, and it came in a really beat up cabinet, which we left in GA but son has not gotten around to having a bonfire yet, so it's still in his garage.
So mostly - price is more of luck issue than anything else.