Here's a basic rundown of what you need to get Map Monkey working
You obviously need to purchase some maps to get any sort of useful functionality out of Map Monkey. For the US I've heard about a trial version of destinator that includes the full maps for $15. Someone needs to check the legality of using these maps before I start giving links though.
For the UK, you can purchase the maps here for £72
Most other maps (including US) can be purchased at stores like this
The "Major Road of..." maps, while being cheap, aren't very good for normal routing as they're most likely to only show highways/motorways and have very little detail. You should only purchase these if you regulary make long trips (particulary the US, where the maps are split into several zones...having the major roads map makes it easy to route across them)
This now needs to be purchased and can be obtained here. You might aswell buy the cheapest support option, seeing as you aren't going to be doing any development with it that will require support. That will be $50.
There's still some confusion with this at the time of writing. When you purchase the SDK, you will be emailed the same trial version you already have. Ignore this and send an email to email@example.com stating you have purchased the SDK and require the DestDLL_08_05.zip file. When you receive this, overwrite the DLL in the DestinatorApps\Destinator folder with that one.