According to OpenSecrets[0] (MPAA PAC), it’s $100k - $200k, or about $1k - $5k per politician. That’s actually a lot less than I expected
[0]: https://www.opensecrets.org/pacs/lookup2.php?strID=C00139519
[0]: https://www.opensecrets.org/pacs/lookup2.php?strID=C00139519
What's the now?!
[0] https://www.metrotimes.com/detroit/how-dan-gilbert-just-scor...
If you just show up and dump $300k on some politicians laps, the effect isn't likely to be particularly overwhelming. You need to cultivate relationships, wait for a good moment (when the money is disproportionately valuable to said politician), at least sell the perception that you're able and willing to dish up more in the future, etc.
So the actual cost is a lot higher than the amount the politician actually receives.