Jamburglar are you confused about offers and acceptance. PostIng a forsale ad is not an offer. An offer is made by the buyer not the seller. The seller accepts the offer. There is no way a buyer posting "pm sent" makes the seller bound in any way shape or form. Now if the seller accepts the BUYERS offer then yes there is a contract.
No, I'm not confused, I understand completely. But I think that, out of all of the posts going on in this thread, you come the closest to getting it right. The problem is we're dealing with complex subject matter and my caveats keep getting glossed over or ignored.
Usually, a "for sale" ad is not an offer, but an invitation to bargain.
See Restatement (Second) of Contracts § 26, pp. 75-76 (1981); 1 Corbin on Contracts § 25, pp. 74-75 (1950). However, where the offer is clear, definite, and explicit, and leaves nothing open for negotiation, it constitutes an offer, acceptance of which will complete the contract.
See Lefkowitz v. Great Minneapolis Surplus Store, Inc., 251 Minn. 188, 191, 86 N.W.2d 689, 691 (1957).See also Izadi v. Machado (Gus) Ford, Inc., 550 So.2d 1135, 1139 (Fla. Dist. Ct. App. 1989); Osage Homestead, Inc. v. Sutphin, 657 S.W.2d 346, 351-52 (Mo. App. 1983); R.E. Crummer & Co. v. Nuveen, 147 F.2d 3, 5 (7th Cir. 1945); Oliver v. Henley, 21 S.W.2d 576, 578-79 (Tex. Civ. App. 1929).
Wade sort of gets this right in his last post but he got caught up in trying to parse language quoted from a US Supreme Court case and ended up getting on the wrong track. He ultimately hits on the right answer though, which is, usually, the initial "for sale" post is not going to constitute an offer because it is not clear enough, and leaves things open for negotiation. As he said, the ad is usually too ambigous to constitute an offer.
If you look at my very first post in this thread, I covered this. I said:
. . .Technically, if your post is worded in a way that constitutes a legal offer, and then someone e-mails you saying "I accept your offer" (or something to that effect) then you have a legally binding contract . . .
The thing is, you're unlikely to get that sort of clean transaction in the real world . . .
The reason these for sale posts are unlikely to be considered offers is because they often leave shipping and other essential terms open to negotiation (like Wade points out.) It has nothing to do with some principal that sellers can't make offers. That's fundamentally wrong. Both buyers and sellers can make offers.
Where things start to get sticky is when you see for sale post says something like "Joust PCB for sale, $50.00 shipped to anywhere in the 50 states, paypal only". That's pretty clear, definate, and explicit, and leaves nothing (material) open for negotiation. It's not uncommon to see that sort of post, and there's a damn good argument it's an offer. A post or PM saying "I'll take it, I'll pay you $50.00 as soon as you give me your paypal address) would be the acceptance. The consideration is the exchange of promises. Offer + acceptance + consideation = binding contract.
Again (and I don't know how many times I've said this now), this may be fairly interesting from a theoretical standpoint, but most posts aren't offers, they're merely invitations to bargain, and nobody is going to sue over $50 anyway. It doesn't really matter how the legalites break down. The better point (from my perspective) is that there's obviously a lot of people out there who have expectations that aren't being met, and whether those expectations are "right" or "wrong" buyers get pissed and then don't want to buy from certain people. It's a lot better to be clear from the get go so that people don't get the wrong idea.
I was simply saying those who follow the "cash in hand first" (which are quite a large number of people in general, not necessarily just people here at KLOV) would have killed my most recent opportunity, and I'm simply glad it didn't go down that way. 
