Adventures with the Italians and Stamps

Where do you buy stamps? And how many stamps does one need to send a postcard from gorgeous Italia to serious Germany, or from sunny, carefree Italia to Trumpesque America (or what's left of America--congratulations, ye of the chicken balloon with T's head on the White House lawn). 
Ask three Italians, get three answers. 
One is usually sent to the "Tabacchi,"a little shop selling stamps and the knowledge of how many to use in addition to newspapers and tobacco.
At reception in our hotel (run by teenagers) I got the vaguest of answers. But very sweet, polite answers. For examples, 
"Oh, to USA? I think, maybe two euro. But you ask at the Tabacchi."
Where was this Tabacchi? https://www.tripsavvy.com/what-is-a-tabacchi-in-italy-1547549
"Oh, easy, five minute!" Yes. Five Italian minutes. I did question the teenager in detail--I all but asked for a map. I walked in the directions she'd suggested. No Tabacchi. An old woman rode by on a bike, crooning in a raspy voice to her orange cat, who was in a cage affixed to her handlebars. The cat seemed eager to be taken to a party.
I had no idea where I was, and asked a bus driver if he spoke English. 
"Leetle beet," said he. The standard response. But he pointed me in the right direction. When I got to "Stop," I should turn left. At least, that is how I understood his instructions. I also thought he meant "Stop at the next street." But what he actually meant was "Stop at the big STOP sign at he end of that very long street." And turn left. And go through twisty, turny alleyways until the sign "Tabacchi" appears and the shopkeeper lets you know someone sold your husband the Italian equivalent of Federal Express stamps for Germany ("He only need one euro! Not-a one euro thirty.) Plus you do get the right number of stamps for the USA--a whopping 2 euros 20 for a post card. Where do I mail them? 
"The Lotto place!"
I looked. Finally a little old lady showed me the red post box, which was down the street from the "lotto place."
I shot my postcards into the Italian post box. Will they land? Anywhere?