How can you get a notebook online at low cost?

So no big data transfer rate. Just "low budget".

Checks are not quite so…

Find out the cheapest rate of all providers in your environment and take that.

Surf stick with a data plan (1 GB usually for about 5 euro per month).

Park in front of a McDonalds and scrounge there Wi-Fi. Or create a hotspot with your smartphone.