Right now, you're able to select the appropriate gender marker on your passport without a note from a medical professional (and a passport can be used in the vast majority of situations you'd use a birth certificate) but because the self select gender marker was done by executive action, it's extremely likely to be reversed when Trump takes office.
Well, I hope things get better. I can suggest all the obvious things: find a local mutual aid group to raise the $200 for the passport fee, I think right now a lot of liberals would love to support a trans person in need. Maybe you have friends or family who would be willing to help, but even if not there might be a local trans community you could try to connect with and they might be able to help or know people able to help.
Either way, I understand if the challenges are too great - some things can remain perpetually out of reach.
Get a passport card. It is legally the same as a passport book within the US (it can also be used for international land and sea travel within North America). It's only $30 to apply and a $35 issuance fee. $65 in total for a piece of RealID-compliant identification valid worldwide for ten years.