The amount of hair falling out is unusually severe. What is the cost of hair loss treatment?

I find myself staring intently at just my parting. I used to hear quite a few people say I had thick hair... but at some point, it feels like the crown of my head started getting thin.

I'm looking into hair loss treatments before it's too late, but I'm taken aback by how many types there are and how steep the costs are... Many of the names are unfamiliar, so I have absolutely no idea where to prioritize or set a budget.

For those of you currently undergoing hair loss treatments, how much does the monthly maintenance usually cost? I'm not sure if I can afford it... Rather than focusing on cost-effectiveness, if there is a treatment that can definitely stop hair loss or help with hair regrowth, which one would be the best?

I don't want to waste time going to an unverified place, so I need advice from those with actual experience.