HELP WITH SUBSCRITION

I HAVE A NANO IPOD .I AM ONLY INTERESTED IN BUYING A SONG EVERY NOW AND THEN AND SYNCING IT TO MY IPOD. I USED TO PURCHASE A ITUNES MONEY CARD AND ADD IT TO MY ACCOUNT IN ITUNES ON THE INTERNETTHEN BUY MY SONG AND PAY AND SYNC. I THINK THAT HAS GONE.

RECENTLY I JOINED A SUBSCRITION OF $11.99 A MONTH BUT I STILL PURCHASE ONLY A SONG NOW AND THEN I SEEM TO PAY FOR THE PURCHASE AS WELL AS THE SUBSCRIPTION AND IT IS REALLY NOT FOR ME ITS TOO BIG FOR THE PHONE SCREEN AND I HAVEN'T A CLUE WHAT IT IS ABOUT. TRIED TO CONTACT APPLE TO NO AVAIL. I DON'T WATCH MOVIES OR ANYTHING LIKE THAT AND AM NOT INTERESTED IN DOING SO.

HOW DO I PURCHASE~PAY~SYNC TO THE IPOD ON THE COMPUTER. HOPE SOMEONE CAN ADVISE LOVE MY NANO IPOD