Often these 'tickets' are not really tickets, but are promotional offers ... for your $40 you may only get a brochure that lets you 'register' (for an additional fee to a separate travel agent) for the hotel stays deal mentioned by pynchonesque above.

The eBay seller is legitimate - he/she is acting as a promotional agent for the travel agency, much like the timeshare sharks at resorts. Legal - yes, ethical - ??

So, feedback ratings are not always a perfect way to monitor whether the deal is good (although I would recommend being very suspicious of sellers with more than 1% negative ratings).