Bitcoin isn't 100 percent secure — here's how to further hide your purchases

The whole idea of really being truly invisible is a disconnect between you as the user and your first connection to the internet.
If you use bitcoin, there is a blockchain. And the blockchain is really traceable.
In fact, during the trial of Ross Ulbricht, the guy that was accused of running the drug emporium Silk Road, they were able to trace millions of dollars of transactions to the wallet on his computer. So to try to anonymize bitcoin, you can go to a bitcoin ATM.
You could buy it from person-to-person on the street, which is probably the safest way if you're using a phone that's not really registered to you. Like a burner device.
Or you could use services that launder bitcoin. So you could buy bitcoin, for example, with a pre-paid card. You can go to any of the pharmacies, buy prepaid gift cards.
You could go to certain sites and actually convert that to bitcoin for a large fee, and then you could go take that bitcoin and launder it even further. They have laundering sites.
So you basically send bitcoin to them, and they'll mix it with other people's bitcoins, and eventually send you bitcoin back with a small fee that's deducted from the transaction.
And then, when you have this clean bitcoin, you could use it, for example, to top up data cards or to purchase email accounts, where you have to sign up for a subscription to make it really hard to trace you as the anonymous user behind it.