Everyone mentions the tiles and ceramics of Portugal and Sintra. But one of my goals while in Portugal was to find a gold butterfly for my charm bracelet. Sintra was the destination in which I found it. Filagree work is very popular in Portugal, and I had seen many lovely filagree butterfly brooches but only one pendant. Having been to around 15 different shops in Lisbon I had a pretty good idea of what the cost would be. The butterfly I found in Sintra cost me 100 euro less than an identical one I saw in Lisbon. Now that is serious savings!
I also picked up a pretty pair of earrings for 17 euro which I then saw in Lisbon airport for 45 euro. (Have you ever found a duty free shop that is actually cheaper for anything but alcohol? I haven't!)
So I recommend the jewellry shops of Sintra for pretty, and reasonably priced gold jewellry.
What to buy: Do check out the ceramics etc, but make sure you pop into the jewellry shops!
What to pay: My 19 ct gold butterfly was 154 euro.