Exactly.
Remember that there are three data tariffs for internet usage:
- volume-based billing at € 0.24/MB, which is the preactivated standard option
- daily flat ("Tagesflatrate") for € 2.50/calendar day with a cap at €25/calendar month (basicly internet is for free after the 10th day of usage within a calendar month), which can be activated through customer care (call 80000 or send a message through the contact form on their website)
Alternatively to these you can activate the "Handy-Internet-Paket" for € 9.95 which will give you an internet flatrate valid for 30 days with bandwidth throttling after exceeding a total data volume of 500MB.
To subscribe to the "Handy-Internet-Paket" send a text message with "START HANDYINTERNET" to 36642.
It will be extended automatically for the next 30 days if there's enough balance left. Otherwise it will be disabled and won't be re-enabled automatically if you top up later. If you wish to unsubscribe manually send "STOPP HANDYINTERNET" to 36642.
The "Handy-Internet-Paket" is being activated on top of the two aforementioned data tariffs, so as soon as the "Handy-Internet-Paket" is disabled you'll fall back to one of the tariffs above (depending which you had before).