The Golfshake system is completely free to join and use and track scores for yourself and friends plus free to set up a golf society/group. Additionally you are able to create 'managed accounts' and track scores for other golfers that are not members of Golfshake.
In terms of tracking scores for multiple players and pricing there are 3 options available:
Free Standard Account
The free service allows you to track unlimited rounds on multiple courses and maintain the handicaps and does provide some group functionality as well as allowing you to run 4 managed account. The free service will also allow you to create a group.
Premium Account (£9.95 per year)
You need to upgrade to the Premium service if you want to run managed accounts for more than 4 golfers. The Premium accounts also provides full group/society functionality in terms of running events, leaderboards and reporting.
Group Service (from £49.95)
This service is primarily aimed at societies that also require a golf handicap member card for their players.
For more information visit: http://www.golfshake.com/services/platinum-account-group/