A big advantage of owning a Garmin GPS device over some of it's competitors, is the ability to use alternative maps, some of which are free. Please note that a lot of Garmin devices use a single file to contain maps, if this file is replaced with a new one, old maps will be lost, However the single file can hold multiple maps and new maps can be added to this file using Basecamp.
One source of alternative maps is called Open Street Maps:-
This project has been running for some years and is edited by members of the public, in order to "create and provide free geographic data, such as street maps, to anyone", files downloaded directly from OSM are not compatible with Garmin Units, However other websites convert OSM maps for use on Garmin units, the files can be downloaded using the links below and installed into Basecamp or directly onto a Garmin GPS :-
TalkyToaster UK Coverage
Userbeam World Coverage
TK World Coverage
Freizeitkarte World Coverage
Bbbike Worldwide Coverage
Open Map Chest Worldwide Coverage (Free Torrent)
NOTE If the free downloaded maps are displaying with black backgrounds, you may need to set :- Menu >> Setup >> Marine >> Marine Chart Mode = Off
