I've purchased 2x in Orvieto, once in Ravello, once in Deruta, once in Assisi. It's NOT cheap for good products.
Each time I've bought, I've hand carried my purchase home. I never ship, and I never pack it in my carry on, or check it in luggage. (I highly recommend that you bring a special canvas or nylon bag just to carry your purchase home)
In Assisi I bought a large serving bowl and 4 smaller individual bowls...all made it home just fine. In Ravello I bought 2 canisters. In Orvieto I bought an olive oil jar on one trip and a cookie jar and a bowl on the next trip.
The serving bowl and 4 smaller bowls in Assisi were @$!50. That was in 2007. The canisters were @$70 and $90 each, in 08. The cookie jar was $125 in 2009.
I can tell you it seems less expensive to purchase in Italy than on-line in the US. I get email from a ceramic importer and am always shocked at the prices.
In Orvieto there is ONE fantastic shop. (sorry, I can't remember the name, but you will know it when you walk in- you can see the difference of quality and choices) the artist is actually at the store...and they have really original pieces. If you see a ton of the same stuff, walk away, it's not the quality you want (unless you are just shopping price) In Deruta - if you go to the actual town (on the top of the hill) the prices will be higher, but the quality better. If you shop the factory stores down the hill, you will find products mass produced for Pier 1 !
All that bring said, you will know what you want when you see it! You are looking for the pattern/colors that appeal to you and to your new kitchen. I LOVE the pieces I have bought during my trips and I use them all every day! Can't wait for our next trip so I can add more pieces!