Prices of PtP tickets

Yes, you're going to Rail Europe, who is notorious for overcharging.

Go to www.trenitalia.com. You probably can´t buy tickets there, but you can get prices, and they are the actual station prices.

okay, thanks for the info on raileurope...Trenitalia will let me purchase the initial train ticket to Rome, but not the return one? I'm such a planner, I can't imagine "just going to the train station and purchasing the ticket at the time I want to go." What if the train is scheduled to leave at 5:50? Can I buy a ticket that early the same day?

Yes, you can buy the ticket earlier that day, or even the day before. Go to a ticket machine or to the ticket window.

okay, I was looking at the Bahn website and the trenitalia website and it won't show me purchase prices. Is it really this difficult or am I just overthinking?

You may be operating too far out. Bahn won't give you prices, since the journey doesn't involve Germany...but it is excellent for schedules and routing. As for Trenitalia, I believe it will only give you prices 60 days out, so use a similar day of the week but within 60 days. A quick look shows the walkup price for second class tickets is about 40 Euro for a 1:40 trip on the fast trains. For the IC (Intercity trains), it's about 27 Euro for a 2:50 journey. If you book as soon as you arrive in Italy, you may get a limited Amica fare, which will save you another 20%.

Linda: You can't buy tickets online at Trenitalia with an American credit card.

Norm, thanks for the tip. You guys are awesome. Kent, as usual, you are correct. THANKS!