Lidl

[inquisitor]

Lidl is not only based on the same network and billing platform like Fonic, but Lidl SIMs are actually realized through Fonic as you may see from the small print on the backside of the SIM's retail package. In my opinion Lidl is the best option for travellers in Germany and also highly attractive to residents.
The difference between Lidl and Fonic are the lower data rates of Lidl and the fact that you can recharge Lidl SIMs only at Lidl supermarkets, while Fonic recharge vouchers are available at several other retailers. Further Lidl's smallest recharge voucher amounts to € 15 while the smallest Fonic voucher has a value for € 20.
I've written an article about Lidl on the PWIA-wiki: LIDL mobile - Prepaid Wireless Internet Access

Due to their anniversary Lidl currently sell their SIM cards for only € 5 (instead of € 10) including € 10 of initial credit and I've picked up a spare one, which I hereby offer to the PrePaidGSM community. It's still sealed and not activated. Besides the original price of € 5 I would just charge the shipping fees of € 3.50 for insured international shipping + € 0.75 PayPal fees and I would appreciate if you provided my Lidl number upon activation, so the buyer and I do each get € 5 from their referral program.