I'm in the UK and got my ADHD diagnosis on the NHS (well, via Right To Choose) so the maximum I'll ever pay for my medication is about US$150/year. [1]
If I had a private diagnosis I'd be paying about half that a month for the same medication.
Anyone with a BMI over 35 is likely to qualify for GLP-1 type drugs on the NHS too. Not sure how long they'll keep prescribing them to you if you take them and lose lots of weight. Most people I know on GLP-1 type things are paying lots (US$200 or more) a month privately.
1. £114.50 for a Prepayment Certificate covering all prescriptions for a year: https://www.nhsbsa.nhs.uk/help-nhs-prescription-costs/nhs-pr...