Those are desirable weights, as far as I know.
Bill (Drumaholic) can probably just tell you the expected price range off the top of his head. So can Mark (BosLover). Me? I have to collect data and analyze it, and then look up the results I've stored. I'm in the very early stages of collecting data but so far the eBay completed auction data suggest:
The 14" Hi hats - $450-$1200 median $580 (we use the median because the distribution is skewed by one $1200 auction of a New Stamp pair 724g/844g in excellent condition). The expected range is more like $450 - $750
The 18": Expected range $500 - $750
But treat these are preliminary until those who know just by glancing at them tell us what they believe.
The expected range is set so that 80% of the time the price will fall into the expected range. The other 20% of the time it can be lower or higher. Prices are quite variable so it always pays to remember that the very same cymbal might get $100 more or $100 less depending on the individual day, the reputation of the seller, the quality of the ad (as in good pictures, good sound files). Expected prices also differ depending on what Country you are selling in, and off eBay sales are different.