Most of the money in politics isn't direct contribution to candidates, it's PACs.

PACs are just groups that do advocacy of some sort. Some do things like advise congress people on legislation they'd like passed, some run ads to campaign for positions or candidates, some advocate for movements.

What they're not supposed to be doing is directly coordinating with a candidate, or running ads just for a candidate. But that's a line that has been continually fuzzed.

An example of a good PAC might be something like the HRC (human rights commission) that campaigns for LGBTQ rights.