In this world of Metadata, it's not easy to make yourself hard to track. Not easy at all. But it's not impossible.
How to get a phone. It's not easy, or quick, but you will end up with one that isn't clearly associated with you.
How to use it. This is harder than you might think. It's all about Opsec.
You won't be off the grid, but you'll be a lot more private than most people. Whether that will attract attention or not is unclear.