Many times you can purchase the same teacup for less on EBay than you can at a shop. Like D&b said the shop seller has to cover costs....but the mentality of buyers is that they will usually pay more in a store.
The fun and mentality of EBay is that you can get a good deal....what most people don't consider is that they may end up paying the same amount for the item even tho' they got it for a lower price because they don't figure in the shipping/handling costs. I speak to lots of people that say I got an item just like that for $12.00 on Ebay and they are asking $20 for it in this store. Then when asked how much for S/H...they paid $8, $10.00, etc....so they paid the same or many times more! I myself have been guilty of that in the past.
If you are purchasing for you....you need to buy the pattern/manufacturer that makes you happy. Be cautious when buying high end collectibles just for investment. It's kind of like the stock market - it may be at the high end and not go higher....or it may go higher - but not in your lifetime.
The greater deals which offer more money in return are not necessarily at collector's shows. There are some good deals to be had, but people who attend are in a mind set that they will usually pay more. The buzz of the event is irreplaceable and the information/knowledge that you learn are priceless so they are worthwhile if that is the area you want to learn more about.