Personally, I find it extremely frustrating to spot an item (any item) in a store or on sale that I really like and then either fail to buy it or put it on lay-away, only to find it gone the next week (or even next day). :x
Since my usual reason for not purchasing an item is lack of funds, I believe that to speak to the owner and put a small down-payment (earnest money) on the item is preferable to watching the item disappear. In most cases the seller will hold the item for some reasonable period until the funds become available. :P But what I really can't handle is when the seller won't!

I know there are reasons for this, including the possibility of another interested buyer. :( But if the seller will at least be honest about this then I might be able to float a temporary loan or something until my cash flow frees up.