Cheap prepaid Internet for short stay in Germany? [merged]

[inquisitor]

Today three new dayflat tariffs were announced by German providers.

Tchibo introduced a dayflat for € 2.99/calendar day on the O2 network. Since Fonic already offers a dayflat on the same network for € 2.50 Tchibo's offer isn't overwhelming, but the fact you now have the choice between Germany's cheapest monthly flat on a HSPA-enabled network for € 20, a 500MB volume pack for € 10 and a dayflat for € 3 with a single SIM, is absolutely attractive.

Ja! mobil and Penny mobil, which are subsidaries of Rewe and Penny supermarkets and whose prepaid SIMs are sold in these, announced a dayflat for € 2.49/calendar day on the T-Mobile network. Since T-Mobile provides superior coverage with widespread HSPA-coverage and nationwide EDGE-support, in my eyes this is the best dayflat for Germany so far. Against the background of T-Mobile's dayflat costing € 4.95/day, the price decline is quite impressive.
The dayflats will only be available for special SIM cards called "ja! mobil data" and "Penny Mobil Data", which will also support voice calls at € 0.09/min to all national networks. Both SIMs are rechargable by regular T-Mobile vouchers, so-called "Xtra Cash".

All three offers will be subject to bandwidth-throttling to 64 KBit/s after exceeding 1 GB of traffic per calendar day.