DIY generally should only be used as a last resort. There are lots of risks involved in HRT that you really should have a doctor for. Also, you’ll be unlikely to get dosages right if you can’t get blood levels tested periodically.

As for parents knowing about clinical HRT due to insurance, you might want to check into if your insurance company allows an adult dependent to have confidentiality. A few do, though with consolidation of insurance companies lately, that may no longer be an option in most people’s cases for all documents they produce. You’ll need to ensure that both the EOB/EOP documents that the your parent receives can have diagnosis and lab procedures codes hidden and that prescription claims do not show the prescription name. But the most difficult one to hide usually is the authorizations if you get patches or any other option that is a drug that’s normally only covered in dosages that are used by cis people and requires authorization for higher dosages required by trans people.

And assuming you can get all of that, you need to make sure you use a local pharmacy and not a mail-order one connected to your insurance as they often leak the information, and make sure you talk to the pharmacist to ensure that they will keep your records confidential, even from a parent.

Unfortunately, all of these things are difficult to control, so you could try to find a clinic whose fees work on a sliding scale based on income to get monitoring and blood tests, and do the DIY.

Also, $20 is a pretty small amount. To get good quality, safe DIY HRT, you likely will need to spend more unless you grow some of the plants yourself and learn how to properly test, process, and use them. The supplement industry is full of fakes or outright dangerous products. And DIY can only provide supplementation, not androgen blockers.

For me, I’m lucky enough that I’ve never needed androgen blockers, but that’s not true of everyone. Tangent, but there’s not good data on how often people need them since trans care is all off-label drug usages and so have little to no funding for research. But it’s becoming more widely practiced to wait to start the blockers to see if they are needed or not, now that it’s better understood how the body often chooses which hormones (estrogens or androgens) to produce by which is more prevalent after the blood is flooded with one over the other for some time. It used to be thought that testosterone was dominant, but it’s looking like that idea might have just been patriarchal medicine at work. Unfortunately, once you start blockers, you are likely to need them indefinitely unless you have some surgeries. This is likely due to a poorly understood feedback loop that’s created likely similar to how overuse of artificial sweeteners confuses the body into not producing the right amount of insulin when consuming real sugar. Once the body gets stuck in those kinds of loops with hormone production it’s difficult to get out of them.

But I’m not a doctor, so don’t take any of this as medical advice, just my 2 cents as someone deeply involved in trans issues and the health insurance industry.