Welcome!
In-car satellite navigation systems used to be the preserve of those with flashy cars and big wallets. Yet, as the technology has improved, the prices of lower-end models have fallen dramatically, and now it's possible to get some models for less than £100.
All the models below rely on GPS (Global Positioning System). This means they receive signals from satellites which tell them exactly where they are on the globe. You just type in a postcode and they'll figure out how to get there, hopefully saving you time and energy, not to mention arguments. Bear in mind though that even with all this fancy technology, they're not 100% reliable.
To stay up to date you'll need to pay for updates every once in a while. Prices vary depending on which model you have, but expect to pay at least £20 each time, plus extra for speed camera locations (these can also be paid for separately).
If you want to buy maps of other countries, you'll probably need to invest in a new memory card full of maps which can cost up to £100.