Quoted from Monk:

It's interesting to me that some of you won't deal with a person that talks money before seeing the item in person. If I'm talking with someone about buying their machine, I usually ask about price before I see it in person. I'll typically look at the pictures ask any questions I have then talk price. Then if we agree on a price I tell the seller I'll take it as long as it is as described. This has worked out well and only one time did I show up and the machine was nowhere near the condition expected. On that one occasion I told the seller I could not pay what we discussed for xy and z reasons and walked away (multiple items did not work and it did a factory reset upon startup which was not disclosed). All other purchases I have showed up looked at the machine and handed over the cash as agreed upon. I have even used this method to purchase other items, including a boat, without issue.
As far as this situation is concerned, I have no problem with what the seller did here. Although I would have just sent you a message saying it was sold.