ZD – The fact that eBay returns results that do not at all seem to fit what you are searching for, has nothing to do with the price manipulation that RebYidd23 asked about. It is something they call Best Match, and it stinks. Amazon also does this, and I hate it there too.
However, unlike Amazon, on eBay there is a simple solution – you can change the results list to “Cheapest” or something else. Then it reverts to exact match only. Best Match is just the default listing order.
On Amazon, if you search by price, you will get tons of garbage listings that do not match at all. Any search other than the ‘Relevence’ sort order is totally useless.