For me, im more of a bargain spotter than setting my sights on a particular item, so when the actual price isnt listed then i'll simply disregard the item, assuming it's gonna be too expensive for me!
However, if i knew a set of wheels i liked was £1200 for example, i would then have the target in my mind of how much i needed.
I understand why they dont show prices, but it really winds me up. Also, i'll never PM a trader to ask for a price, as 99% of the time i wont want the item, and i'll feel like im wasting their time.