What do you guys spend your Professional Development Budget on?

Just wondering how other SWEs spend their PD budgets on. Conferences? Online courses? Books? Do you guys have anything that you guys particularly enjoyed or recommend? For a bit of context, I am SWE with 2 YOE, mostly working on backend projects. I do not hold a CS degree so I've been looking at some CS courses but I did notice a lot of free resources (like https://github.com/ossu/computer-science). I have until the end of the calendar year to spend this budget that is "use it or lose it" so looking for something where I can drop some cash $$.