Yi cloud service card / code

Hi everyone, my Yi Home camera cloud plan has just ended. Last time I purchased a 12 month sub via ebay, the seller sent me a code to enter and bingo..... 12 months sub without card details or monthly payments.
Ive had a quick search online and eBay again and it seems the service cards are longer freely available. Suggestions anyone before buying the 'legit' way?
TIA