Good price? Do you mean a fair price? I'd say 20K-50K per item, but I've seen some really crazy prices.
It really depends on which imbuing resource and which shard and how many you have. Some are harder to get and all the essences are found on the new treasure chests. The best bet is to look at the resource vendors on your shard and price accordingly - higher prices mean they will stay on your vendor longer and you pay more vendor fees. I like to price mine lower for faster turnover.