Garmin Forerunner 945 downloading UK map

I received Garmin 945 as a gift from a friend in US, but I live in UK. I want to download UK and Europe maps on it, but it seems I need to pay for it... And there is a free version???

Can someone clarify a few questions I have? 

1. Can I download UK map on my US version? and which paid version do i need to download? 

2. Where can I find free map? 

3. Is free map alright for triathlon? 

Many thanks, guys!