There's some simple fundamentals.
And none of them have to be expensive.
At it's core we're talking about water, beans and something to brew them together in. If you like the way it tastes, then your main aim is to know what you did so you can repeat it tomorrow. As equipment scales up in complexity and price, that's most of what is being attempted - tighter control over water, coffee grinding and the brewing conditions.
We think a good place to start is with what you like to drink, and from there we can show you how to get there with a different range of budgets.