Cash is the only truly anonymous method of payment. Bitcoin has a ledger that will be around forever. Eventually computer forensics will be able to use that ledger to peg transactions to IP addresses or possibly trace it straight to the user with the help of ISPs. If you really want to be anonymous when you buy online I suggest Simon Gift Cards and Debit Cards.
https://www.simon.com/giftcard/Do you understand how the blockchain works? It never records the IP address from which the transaction was sent. How would Gift Cards or Debit cards be more anonymous? Those are linked to a name and address, whereas Bitcoin addresses are only linked to a 30-some character string of random numbers and letters?
Maybe you should read up on that first before you sound so sure.