Methods to have Wi-Fi on the go with my laptop?

What methods are there for how I can access the Internet on the go with my laptop and what are the best methods?

Then you don't call it WLAN, but 'mobile data'!

You can 'shimmy' from HotSpot to HotSpot, eg at McCafes, or places where there's a chargeable WLAN (eg Telekom, ok, then it's WLAN after all).

In ICEs there's also WLAN, I don't really know how it's used.

You can use your own cell phone, via cable, BT, or WLAN, but this costs a lot of battery power.

You can operate an extra mobile HotSpot with your own SIM. Ultimately like a cell phone, with a large battery, but with an extra SIM and contract.

You can operate a USB stick with SIM directly on the laptop or with a cable.

In the past there were extra expansion slots on business laptops (e.g. PCMCIA), where the corresponding cards could be inserted.

In current (and expensive) business laptops, a handset is integrated into which a SIM can be inserted. Ultimately like an iPad with LTE…

UMTS card?