I don't think you paid too much, but there are overlay sulphides from Baccarat with the correct etched mark; overlay sulphides made by Baccarat ( I think) for the Franklin Mint, marked as such; overlay sulphides made in Murano; and overlay sulphides made in Murano with fake Baccarat marks. The Murano ones can be very high quality, but the overlay is often thicker than the Baccarat ones. Many have good waffle cut bases. The overlay in your image looks fairly thick, so I suspect Murano.
I'm not certain what the going rate is, but I don't think that these sulphides - regardless of maker - fetch more than $40 - $60 normally, as there are a lot in circulation. If anyone thinks otherwise, I have one that I would willingly part with for $100!