MasterCard is accepted almost anywhere in the US that accepts Visa. In approximate order of acceptance in the US: Visa, MasterCard, Discover, American Express, everything else (e.g. Diner's Club).

AFAIK, master card is accepted anywhere visa is accepted. In the old days you may see a few stores that do not accept master card. not any longer though.

My Dutch Mastercard was not accepted at the website of Y-Mobile last year. I asked the question at TúYo and they told me I should use a USA based credit card. I will still buy a Tuyo card though and see if it works. I will be in the states for 4 weeks and it's cheap and without any callback or callthrough services.

Edit, I just saw you can top-up online with a top up card as well. I think I'll justbuy a bunch and top up 3 times before I am back in the states again.

Amex cards may be the best bet as they've yet to implement ZIP code matching as part of the authorization process.

I just ordered a Tuyo card from eBay. As soon as I get it I will try to top it up with a French issued debit VISA.

That may be the first time I'll have a benefit from my AmEx card, for which I'm paying yearly fees without having any advantage against my free Visa and MasterCard.

lol, I've got two reactions yesterday from my one question: "I am from Europe and am planning to visit the states in Februari as I do every year. I would like to buy a sim card but would like to use it every year without the need to get a new number every time. Therefore my
question: is it possible to recharge my balance with an European credit card? With T-Mobile this unfortunately doesn't work for example."

Answer one yesterday: "Thank you for contacting TuYo mobile. Please rest assured we will work our hardest in answering any and all your questions. In regards to your question, unfortunately you must use a U.S. credit card to reload a Tuyo account. Hope this answers your question. If you have any further questions or concerns do not hesitate to call us at :
1-800-get-tuyo(438-8898) or dial 611 from any TuYo handset."

Answer two: "Thank you for contact regarding your request yes it is possible To recharge from Europe so went you come to the states you would not have to buy a new sim card you can to this on line the link is www.tuyo.com and you can recharge on line or if you have need problem pleas call customer service at 1-877-438-8896 Thank you Customer service"

When I fuel my car, the pump frequently asks me to enter my "zip code" (US postal code). I never considered what would happen if I used a non-US credit card. I guess I could always take it inside to the clerk. I could see how this might be a problem for online purchases.

I was just looking around the tuyo.com website and found a page that mentioned 50c/day for WAP access. It seems you activate the option and get 24 hours of WAP access. Now, I have no idea what "WAP" means to Tuyo. It might be a walled garden or it might have at least some way to access HTML & e-mail, like T-Mobile's T-Zones.

Tuyo looks interesting. The only disadvantages I see are the poor coverage and 90-day validity.

I noticed CallingMart.com sells Tuyo refills. No sales tax, 3% discount and best of all... <b>PayPal payments</b>.

I wouldn't say that. I use my MasterCard every time I go there (I don't know that I've used a VISA card in the USA since the 1980s).

I haven't seen a merchant that would accept VISA but not MasterCard in many years, either here in Canada or in the US.