Absolutely negotiate, esp when it involves an inpatient admission and in most cases when it involves an ER encounter or certain outpatient services. Wife was admitted back in Jan. We got initial bills totally ~$90k. Lots of stupid in there. We were on the hook for I think like $6k (on a HDHP). Told her to file away any bills that come in for the next couple months and don't send them shit until the adjudication process work out. Haven't done the math on the final out of pocket, but it is somewhere under $2500. Fucking ERs are a racket with their in/out of network provider bullshit. I've had ED docs look at me like I have three heads when I asked them to confirm that their provider group was in-network before rendering services. I've also had to bend over and enjoy it when your fn 2 year old needs a lumbar puncture and you have no other realistic emergent option, so you have to negotiate the fees on the back end. If you have a reasonable basis for pushing back on the charges, they will settle for dimes on the dollar. I settled probably a couple thousand in bills for cardiac monitoring device for my son at the beginning of COVID. Figured they needed the money and would make a deal so we made them an offer that I thought was more than reasonable considering the device never transmitted and required a professional interpretation of the data. They accepted and closed the account.
What we need is a system that requires pricing transparency, incentivize price competition, and backstops against catastrophic events. There are relatively straightforward ways to get there, at least conceptually. Too many interests vested in the current system though.