We do not tend to discuss values here, they're far too contentious and not about the glass, which is what we are interested in.
Something is worth what somebody is willing to pay for it, in that place, at that time. You can obtain a ball-park figure by searching sold auctions for similar.
Personally I feel Phoenician is underrated. It is very good quality, a lot of it much better than Gozo, which I find lumpy and a bit crude.