I really don't want everyone else's idea of a 'bargain' being posted here all the time. It would get very messy.
If I want something from eBay I'll look myself and set up an automatic search to notify me of when something I might want gets listed.
If I miss something, and I'm sure I must have over the years, that's my bad planning.
In some contexts the ban is a little silly, particularly in the case of dealers selling multiple items on eBay like the Trend stones last year, but the mods are generally sensible enough to leave posts that clearly benefit members whilst not disadvantaging anyone. Overall there's a degree of sense to it when sensibly moderated.