Please be aware of the following when considering buying maps and other software to use with TomTom Satellite Navigation:-

Unless you are at least 100% certain that the item is Brand New and Sealed, then DO NOT BUY! 

Why?  Well, like Microsoft's Windows, TomTom requires you to "Activate" your software before it will work.  This Activation will "lock" the map to one specific device, therefore making it unusable on any other device, even if it is exactly the same model.

You can confirm this information at TomTom's own website amongst the support pages, where it says:-

"TomTom Navigator requires online software activation. All copies of TomTom Navigator are sold with a product code. This product code can be used to activate the software on one device .... Second hand TomTom Navigator products are likely to have already been activated once or more by the first buyer and the product code may therefore no longer be valid. For this reason we advise our customers not to purchase TomTom Navigator second hand. If you have already purchased a second hand TomTom Navigator product and cannot activate the software, we suggest you return it to the seller."

The moral is clear:- if you buy secondhand TomTom maps, they may be cheaper than Brand New, but are no good to you if they won't work.