Do I have to pay for a subscription to use GPS signals?

No you do not need to pay extra to receive GPS signals at any time. The Sureshotgps 8850 and micro both come with a Silver membership which gives you access to the worldwide map database for 12 months and allows you to download up to 3 courses for free. To have access to the map database after 12 months you will need to renew your membership. However if you do not wish to renew the membership after it expires you will still always receive GPS signals for the existing courses loaded on your unit. http://www.sureshotgps.com/membership.php