First of all this may be an old question and I apologise if so. I've borrowed a Garmin 800 to take to Spain as something I can dump files down to from wikiloc and play follow the arrow. It's to supplement the bikefax book (which is rather good) and any mappage I take. Now I am fairly sure there are some free maps I can download to the micro sd but I can't remember what they are called, have seen and heard them referenced in the past and wondered if anyone would mind jogging my decrepit memory.
Open street maps, I think.
If you Google getting them onto a Garmin 800 there will be loads of guides...
I use the maps from OSM for my edge 705. Spanish mapping is never as good as British OS, but it's usable.
Link http://mapas.alternativaslibres.es/descargas.php
You want the peninsular & islas baleares one.
check out talkytoasters website - think he was doing builds of Euro countries (and considers requests!!)
thanks Houndlegs that's a very useful link