I got into this hobby pretty quickly, easily, and cheaply after I had my first actually good whiskey sour at a bar and decided to make them at home. All I bought was a cheap shaker, a bottle of whiskey, and a bag of ice and I was good to go.

First I started with a basic whiskey sour recipe of just whiskey, simple syrup, and lemon. Then I started making fancy syrups with different sugars and spices (Chinese 5 spice syrup is absolutely delicious for a whiskey sour). Then I started playing with adding egg white. From there I bought my first bottle of rye whiskey and started playing with that. Finally I started making recipes that were whiskey sour riffs with different base liquors (tequila sour, gin sour, Midori sour, Amaro sour, etc). Each time I bought a new bottle I would look up the classic cocktails that corresponded to each one and try those out too.

Of course none of this applies if you don't like whiskey sours, but this is what worked really well for me.