SIM cards determines phone number which you send back to USA. SIM card purchased in ITALY will have one phone number and SIM card in Germany, another?????

Yes. You can also purchase a global SIM which would work in multiple countries. Hence, you would have one number.

You are correct. Each SIM card will have a different phone number (including country code, etc.). My husband has several prepaid SIM cards from different countries, that being the cheapest way to manage if you have an unlocked tri or quad band phone, and each has a different number. (Which he programs into his phone so he will remember when he goes back to that country.)

Vodafone prepaid SIM cards have free incoming calls in many or most European countries and text messaging to another cell phone is cheap. We bought a SIM card in Greece recently for 6 Euros (for 8 Euros worth of time) and text-messaged our daughter's cell phone in the US maybe 10-15 times, plus received about the same number of answers. (Much of this trying to find a restaurant she wanted us to try in the Plaka but didn't know the name or location of. ) Never used it for any calls, though we would have been available in case of emergency since our daughter sent the # on to our other daughter and the cat sitter. But we still had about 2 Euros of time left at the end of the trip.

>Vodafone prepaid SIM cards have free incoming calls in many or most European countries

Unfortunately not true. Vodafone are among the most expensive, when used in a country other than they where bought in.

Hi

I use one of these global SIMs when travelling www.globalsimcard.co.uk. It has free incoming calls in Europe and other countries, and pretty good rates to call out.