I'm not rich (or at least, don't feel rich with the enormous cost increases on everything combined with no promotions for 3 years) -- but how do you negotiate with a tradesperson exactly?
All of the major trade companies around where I live (HVAC, plumbing, electrical etc.) in the US have rates that they quote before the person will even show up. As a new homeowner who didn't grow up in the US, that's all I've ever dealt with.
If the answer is “Give them a number you're comfortable with, and just DIY it as an alternative” -- that's fine, and I do it for anything simple; but for the remaining ones, I have already made a determination that learning this skill would be way more in terms of time invested than the $500 or whatever absurd number they are quoting for a simple repair (this logic likely breaks down over time, and I'm trying to invest more time into learning more house repairs).
I have tried pre-purchasing some parts in the past; and asking them to use them for the install -- that one had some success and a guy told me how much his company marks up parts (n00%).
I do try to get multiple quotes for something, but the difference between them isn't usually appreciable; they're all absurdly high. I've tried to ask them for a parts v/s labor breakdown in the past; some won't even provide that.
If it is a company with more than 2 or 3 employees you are already going to be given a significant markup right off the bat for their marketting and commercial office expenses and have obfuscated costs, individual contractors have lower overhead. Location is also important, if I gotta drive an hour each way for a job that is going into the price. Getting legit parts, especially with short notice, also costs more. While I might buy a $8 ignitor on amazon for my own furnace or a friends, I cant risk crappy counterfit parts for regular customers that might blow up in a week so now its a $35+ part.
Buying your own parts can help but can also burn you if its wrong, or cost the same if something extra is needed that wasnt expected and requires a second visit or bought on short notice from a local parts dealer. A contractor often eats the costs of wrong parts they ordered and just hopes they can use it elsewhere later, but if you bought the parts that is just cost on you.
My recommendation, which is still probably of limited help and won't always be worth it, is to start by hiring a local handyman instead of a specialist and having atleast 2 weeks of lead time for parts. Of course finding a worthwhile handyman can have its own difficulties because so many tradesmen leave the industry after realizing corporate contracting pays workers like trash while taking a lot of the most valuable and worthwhile contracting work off the market from independent contractors.
You'd need to be negotiating with an actual tradesperson, not someone who is a glorified salesperson / unskilled installer who works for a company that has been acquired in a PE rollup.
The easiest way to find a good tradesman is to ask another tradesman. There is an HVAC person in my local area who will come out and do most jobs (such as, for example, moving an AC) for about $500. A PE rollup firm would quote $10k for such jobs.