Not a valid contract if costs clause was hidden (Score 1)

In Germany, clauses in contracts that come as a surprise and are not prominently displayed are routinely rejected by courts.

Since your friend was not aware of the extra costs in the "contract", I assume the clause with regards to the costs was not very prominently placed on the page. Also, you can not expect costs on pages that state "free", "at no costs", "opensource" and the like.

Therefore if I were your friend:

1. check if the costly clause was not prominently displayed and disguised by other words like "freeware" "at no costs" etc. and if this is the case:

2. make a screen shot of the page. Print it out, date and sign it.

3. reject the first bill that comes in by a letter with proven delivery ("Einschreiben mit Rueckschein"). In the letter, state that the cost clause came as a surprise and that you therefore do not accept the contract. To be on the safe side, also cancel the Contract at the same time (use the words ("Hiermit widerrufe und kuendige ich ausserdem vorsorglich...").

4. sit back and ignore all further bills and communication from that company or their lawyer and money collector. Don't get nervous if they try to scare you and use big words. Ignore them, you already told them all you had to tell them.

5. once eventually a court signed bill ("Gerichtlicher Mahnbescheid") arrives, you MUST reply to the court to reject this bill! Do not ignore this!

6. see if the company dares to go to court after this. I bet they will not as they will very very likely loose if the cost clause was not obvious.

Good luck!