Dose it cost me Money?

[Lewis Evans]

The phone's contract won't take into account the amount of data you use when you are connected to a Wifi network - provided it works. For instance, you could connect to a BT Homehub that has no access or limited access to the internet - unplugging the connection cable with still allow devices to connect wirelessly. It just means downloads and uploads can not happen - unless between devices connected on the same router.

If the Homehub allows you to connect, but has no internet connection itself, then your phone may just default to its own network provider for data - this will cost you data/money.

To make sure you are not going to burn a hole in your pocket (so to speak), go to your settings, find your network settings and make sure that data download is disabled or unticked. This will still allow your Wifi access.

Ignore the majority of Escape's answer, which was a bit rude, prejudicial, hypocritical and insulting to say the least.