This research has been done on 2010-10-28. Here are the results, by recommendability, the most recommendable first.
Only the first three alternatives seem to be really recommmendable, though.
- .mobook. .basic 6. This is an interesting rate of a Vodafone reseller. 6 months minimum runtime, 5 GiB inclusive traffic (before going down to GPRS speed), 7.2 MBit downstreem speed, for 20 EUR monthly. And probably with the option to upgrade to the XL basic 6 rate. [Source]
- MoobiAir MoobiAir McSIM Datenflat SIM-only. This would be the right rate for trying it all out. It is: Vodafone network, HSDPA speed (7.2 MBit), 5 GiB traffic, 1 month minimum runtime, 27.45 EUR monthly. [Source]
- .mobook. XL basic 6. This is an interesting rate from a Vodafone reseller. 6 months minimum runtime, 10 GiB inclusive volume (before going down to GPRS speed), 14.4 MiB downstream speed, for 40 EUR monthly. However, it is a bit expensive. [Source]
- surf.RED rate with SIM only. Alike to .mobook. .basic 6 (20 EUR monthly, 5 GiB with up to 7.2 MBit), but with 24 months runtime and 25 EUR setup price, so just disadvantages. [Source]
- McSim. This Vodafone reseller offers a prepaid rate with a “handy flat” option for flat rate mobile surfing for 9.95 EUR monthly. However: this is only allowed with a phone, not a computer. And the speed will be limited to UMTS speed on 2010-12-31. [Source]
- Vodafone. The only moderately interesting rate is “Zuhause Web Flat” [Source]. This provides 5 GiB per month with maximum bandwith within a 2 km “homezone” radius, and after that with 64 kbit/s. Cost is 29.95 EUR monthly, with 2 years minimum runtime.
As of the time when doing this research, there are no better data rates availabe in the Vodafone network in Germany, because the following list has been fully worked through: Vodafone monthly flatrates with HSDPA, on billiger-telefonieren.de.