I’m sure you’ve hear about the EL AL glitch in prices a couple weeks ago?
Prices from NY to Israel were $300 (including taxes and sur charges) due to a price error on their site.
A couple days ago there was another error on someone else’s site: They were selling a sweater for $79, but once you ‘add to cart’ it shows as $0.00 and you only had to pay $8 for shipping.
Is it assur to buy these items?
Answer:
If the seller is Jewish, there is certainly a problem of buying the item, because it is a clear case of ona’ah.
Although there is room to debate the application of ona’ah to an airline ticket (it might not be gufo mamon), it will certainly apply to a sweater.
Even if the seller is not Jewish, the case will seemingly fall under the category of mekach ta’us. It is not merely a mistake in pricing; rather, the whole sale is a mistake, because the seller obviously doesn’t mean to give away items for free.
Although ta’uso muteres, this applies specifically to a post-factum level, and not lechatchilah, so that it is hard to be lenient in this matter.
Best wishes.