I do trust the foundation and make a monthly donation, but those donations are not used for Firefox, and I'm not even sure they legally could be the way the foundation is structured. I too would really, really, really like a way to fund Firefox development. I don't use any of the features they make money from (search partnerships, sponsored suggestions, Pocket), and if I'm forced to I will stop using Firefox.

I don't understand why they can't do a pay-what-you-want model. Keep the browser free, but encourage people to pay $20 or something if they like it. I would.