There are many reasons why an item seen on eBay sells for a great price and steadily.
Take to heart the comment jmoon87 made as it is full of wisdom.
There are reasons why you can't find the item at a competitive price.
One is because many people steal these items.
I have stated before that I have read threads in other forums about teens shoplifting to sell on eBay. They exchange methods of stealing and do it with regularity.
I won't get into the specifics but they are very skilled in their criminal trade. From knowing where to stand in a store to actually pulling the plugs out of camera recorders.
I would state that probably 5 to 10% of what you see on eBay is stolen goods.