The 10 free credits is a one time Bonus.
You will not receive it again when your subscription renews.
(Due to a server error I recall several members had received a 2nd 10 credits by mistake when they Canceled and renewed. But once Totem found the error, the additional credits were revoked. So if you should accidentally get a Second 10 credit bonus, Totem my at their discretion, revoke those credits given by mistake.)
It starts the Day your subscription goes into effect. but even if you purchased the card on special that day, you will get a card and it will be a card Not Already in your collection.
( Totem uses third party Billers, so the Biller has to notify Totem to start your Subscription. Sometimes there is a delay between when you Purchase, and Totem is notified.)
You will get the full 6 months from the day the Subscription become effective.
Some like the subscription ( it is the most cost effective way to get the cards, and it is the way I built up my Collection.) but what others Don't like, is you have no control over what card you will get for the day. It's selected at Random from the cards you don't already have.