I don't know about you, but I find hard copy books much easier to read than online copies (which sucks as they go out of date quickly).
You could buy several books from O'Reilly.
I also recommend buying The Phoenix Project it's a fictional account of dev ops. An easy and silly read, but good to start a conversation around cultural improvement.
A frame challenge
Don't spend the money just for the sake of it, just because it exists in the budget (just as you wouldn't in your personal life, I expect, if you happened to get an unexpected windfall! You wouldn't say "I received this $200 from an unexpected contractual penalty (or whatever) so now I need to spend it" would you?) I get the feeling that ...
So your budget resets in three weeks. What you're looking for then, is things that can be paid in advance. That should be doable; most companies, including educators, are happy to take money early.
So what are good kinds of professional development to spend it on? I would look at:
A few things to consider.
Unless you are actually planning on leaving, the whole thing is a moot point. If you are planning to stay, it's by far the easiest to just sit it out
Read the contract carefully. Typically these things are pro-rated, for example if you leave right away to repay it all, but the repayment amount should decline over time. It also ...
I've never used any knowledge of that training after that. So I want to know if this training contract is invalid according to the law of the US.
Almost certainly not, since it's near unheard of for contracts of this nature to allow a "get-out" clause if it doesn't turn out to be useful.
The only potential legal avenue I can think of is if ...