united-states commerce
Is it legal to search for commerce sites listing items at erroneously low prices and exploiting such errors?
<p>Occasionally a website will post incorrect prices for items they are selling.  (Maybe it was caused by a typo during their data entry process, or the result of a bug in their code.)  Once they realize their error they correct it.</p>

<p>If I notice the error before they do, and I attempt to buy the item before they fix it, is that legal?  I.e., if I <em>knowingly</em> try to exploit their mistake could I be violating any law?</p>

<p>Now, if I continually monitor websites, waiting for such an error, just so I can buy at erroneously low prices, does that pose any further legal issues? </p>

<p>I'm not hacking or changing their prices.  I'm just waiting to buy until an incorrect price is mistakenly posted.</p>

<p>There may be violations of consumer protection and/or advertising statutes here by the online store, but the common law position is that:</p>

<ol>
<li>The website's owner is making an <a href="https://en.wikipedia.org/wiki/Invitation_to_treat" rel="noreferrer">invitation to treat</a></li>
<li>Based on that, you are making an <a href="https://en.wikipedia.org/wiki/Offer_and_acceptance#Offer" rel="noreferrer">offer</a></li>
<li>The contract comes into place when the website's owner <a href="https://en.wikipedia.org/wiki/Offer_and_acceptance#Acceptance" rel="noreferrer">accepts</a> your offer.</li>
<li><a href="https://en.wikipedia.org/wiki/Offer_and_acceptance#Time_of_contract_formation" rel="noreferrer">The time of contract formation</a> is "when the parties give objective manifestation of an intent to form the contract."</li>
</ol>

<p>You would need to read the site very carefully, in particular their terms and conditions, acknowledgement page and/or email to see if they are actually accepting your offer or if there are conditions attached. If there is no clear, <strong>unconditional</strong> acceptance then there is no contract at that time; this applies even if you have paid for the goods.</p>

<p>If this is the case (and I strongly suspect that it would be for most online stores), then their acceptance of your offer and the formation of the contract probably does not come into effect until they "give objective manifestation of an intent to form the contract" by shipping the goods. Up until that time there <strong>is no contract</strong> and their only obligation to you is to promptly refund your money.</p>

<p>It may or may not be a crime (I will come back to this tomorrow, but I strongly doubt it because there is no deception on your part), but there is another thing at play: if they discover the error before shipping the good, they may well be able to refund you and deny the purchase. A unilateral mistake will often result in a voidable contract if the other party knew of the mistake and intentionally exploited it. (<a href="http://nationalparalegal.edu/public_documents/courseware_asp_files/contracts/DefensesToFormation/Mistake.asp" rel="nofollow">source</a>)</p>
