No one here is mentioning this, and you can only say it if you’re truly good and this is the truth: “I believe I will bring much more than $40 an hour in value to the company, so this will be a good opportunity for both of us.”
Yeah, they may be negotiating with other people, but if you are the best candidate then it would be stupid to save one or two dollars an hour to go with someone who is less well suited for the job. Then they hire the wrong person, they’ve now wasted 3 months of wages and were set back by 3 months, and will need to hire someone again, and you may not be available then.
They may have hard caps, and if they do, they may say “look, the most we can do for this job is $35 an hour”. Take it if you’re happy with it, and don’t mention salary again - put up work that justifies your wage.
People need to frame the conversation in what value you bring to the company, not what you’re costing the company to be employed. If you weren’t bringing in greater value to the company than your cost, you would be fired. How much of that added value that you can take home is what is determined through negotiation.