robby

I have a TomTom One which is maybe 5-6 years old but works perfect. The map (UK) is as old as the unit so a lot of roads aren't on it but to update the map on the TT site it will be £40!
Is there anywhere i can buy a SD card with an up to date map or another site to download a map?
I've looked on ebay and there are a few cards for sale but they don't say how old the maps are