I come across that all the time and find it annoying as can be as it wastes my time. It should be a report-able issue. It is in listings that have variations where for example you can the listing headline will be for a box of 50 widgets for $5. & when you get there and select the color you want in 50 widgets the price is actually $50, but you can get one widget holder for $5.! There have been times I can not even find the item listed for the presenting price at all. Or as you said, those were all sold out! I have done items with variations and can see how a seller could upload the listing in an acceptable rule following way, but then go in and edit the items to have that happen by design.
I don't know that ebay cares about the bait & switch problems particularly as their algorithms could catch these scams. I imagine you could report the listing as you would any other and just check back in to see if they actually addressed it with the sellers.
I would certainly be curious if someone actually bought when lured in to a listing this way. I never have. Even if I thought the higher price was reasonable for the 50 widgets, I don't appreciate being lured in with a scam. It reminds of years back (I see it only rarely now) when people sold a lot of items with a "reserve" auction. An item would appear to have a low opening bid price and when you went to it, there would be a reserve price. Oftentimes people who were trying to catch attention with a crazy low price on pricey item would actually list what their reserve price was so that hopefully you would start there.
Ebay also used to stop people from listing the same item in 20 different listing and insist that if it was the same thing that you could list with quantities, but I now see plenty of listings where some people have quantities of the same thing so it prevents you from finding the seller you might prefer to buy from as you have to look through all the others to get there.
