Coverage In Germany And Austria

Hi --
I'm so glad to have found this forum, because I can't find decent comparisons of the different SIM cards elsewhere (and it was a pleasant surprise to see the Amnesty International logo on some messages)

My family will be in Germany and Austria in two weeks. We've got a Siemens C60 and are looking for a SIM card.
On ebay I'm finding a t-mobile card for Germany that will cost about $40 (with $15 credit on it). Will I need to register it - and at what cost?
Also find an e-plus card, for which I would need to add credit, but it will cost only about $8. Seems the better deal, but am not sure about coverage.
We will be in and around Salzburg and Garmisch-Partenkirchen. Do I need to worry about coverage with the e-plus card?
Also noted that when using the e-plus card in Austria, calls will go through other networks, does this mean there will be roaming charges in addition to the rather steep (.80/min to receive calls) prices for calling time?

I know we could just buy a card when we're there, but we have a son who will be on a school trip elsewhere, and they need to know at what number they can reach us before we go.

Thanks for any advice you can offer.

[Effendi]

Of course roaming in Austria with a German card involves high roaming fees. I think all German sim cards are VERY expensive there. So, buy the card of the country you are going to spend more time in, or buy 2 sim-cards, one German, one Austrian. For the Austrian I think Yesss could be the best choice, it's a virtuanl operator on GSM1800, good coverage, and you can buy it at many gas-stations or supermarkets.
About Germany I think e-plus has good 1800 coverage, surely it covers Garmisch-Partenkirchen, maybe they don't have the best coverage up on the mountains, but usually there are no problems. $40 for a T-Mob card are too many, you can get a new one in Germany for ? 20.

[snaimon]

IF (big if) you travel away from US often, you might consider an international card like UM, 09, etc. For this trip you would have FREE inbound in both countries. Combine with callbackworld the outbound rate to US is 14 cents / minute. If this is the only foreign trip planned in the next few years, it still might be worth the investment.

Stan