It happened to us & to many tourists we spoke with. When shopping at the souvenier shops near the Vatican our purchases were deliberately added up wrong and we were deliberately given wrong change (both to the shopkeepers advantage by several Euro). Arguing loudly with the shopkeeper, forcing him/her to write the amounts down and add them up by hand, and refusing to back down seemed to work. In one instance the sweet looking grandpa behind the register couldn't seem to add or subtract correctly until we told him he could keep all that we had intended on purchasing & give us our money back.
Unique Suggestions: Pay attention to the prices of what you're getting, add it up yourself before getting to the register, make sure the figures match, and make sure you're getting the correct amount of change back. Really watch the 1 & 2 euro coins as the shopkeepers seemed fond of giving the wrong coin in the hope that you'd notice the number of coins instead of the value of coins given.
Fun Alternatives: We really didn't have any problems in the shops in other areas of Rome. The nicest shopkeepers with the most reasonable prices were far away from the tourist areas.
Please make sure you shop around for that "must have" souvenier. On our last trip to Rome, my daughter wanted a fan (she's only 10). The first place she saw this fan it was 9 euros. I thought this was very overpriced so I talked her into waiting, as it was still early in the day and I didnt want to carry it around all day. About an hour later she saw the exact same fan for 6 euros in a different store on a different street. She started to get the clue that she could get it for a lot less if she just looked around. In the end, she got it from a street vendor for 3 euros (after much haggeling). We all realized that no price is the final price when it comes to souveniers.
Unique Suggestions: If you must buy something, at least tell the vendor of the price you saw offered at another shop and see if they will beat it. My sister did this with a small statue she had seen and the vendor beat the price by two euros. It doesnt hurt to try to haggle, just be realistic. You wont get a twenty dollar statue for 3 dollars but you dont have to pay 40 dollars for it either. Use your head and be willing to walk away. There are plenty of vendors who will come down in price in order to get your business becouse most venders sell the exact same things and are competing with each other for your tourist euro. Fix a price in your head that you will not go over and stick to it. If they don't make a reasonable offer or accept a reasonable offer, walk away and find your treasure at another store.
Fun Alternatives: If a vendor refuses to come down on the price and you see a second item you want, ask if they will give you a deal if you buy both. My sister did this with some purses she found. She got 20 euros taken off the price of 2 bags even though the vendor wouldn't discount just one. She left the store very happy. It never hurts to ask for a discount or lower price. I have found that street vendors are more likely to come down in price than shops but the shops will sometimes come down if you are tenacious and polite and buy several things, and it doesn't hurt to let them overhear you say "I'll just get it back on via cavour (substitute any street name). They had it for 2 euros less". Usually they will call you back and offer you the same deal (they don't have to know this is your first store of the afternoon).
As with most tourist shops & curios, items on sale are mostly overpriced, and generally not of the best quality.
There is plenty of this in Rome.
On the one corner they will sell a drink for 3 euros, and slightly further away from the attraction, they will sell it for 2 euros... be wary of this.
I do think that because they can easily see you are a tourist, they inflate the prices.
It is everywhere.
Books, postcards, memorabelia.
At first it's interesting and one browses through them to see if there's somehting interesting.
But then the novelty wears off and one grows tired of seeing them everywhere.
They are also quite expensive, and totally aimed toward the ignorant tourist. Ask for a discount.
Ensure you get the right change back. We were duped with incorrect change at 2 different stalls, twice. Wasn't a large sum of money, but that's not the point.
Just be careful.
There are way too many souveneir shops selling the same t-shirts and shot glasses.
Unique Suggestions: Just pick an afternoon to spend an hour to pick up all the junk you need to bring back home with you then forget about it for the rest of the time you are there. They tend to suck you in.
Don't pay too much attention on souvenir shops, because you risk to miss a lot of beauty around. Keep in mind, that prices of the same things differ from shop to shop, and those shops that are located near the great tourist attractions, like Colosseum, have the highest ones.
When shop in Rome, one must know that the 'Romans' take their lunch very seriously. All shops are closed during lunch hours. That's me in the street with all the shops closed for lunch.