I'm a physicist who writes research papers using the freeware package "LyX" (based on LaTeX). It's very flexible and easy to use. I highly recommend it!
I became an "independent researcher" after I left my physics research job and moved to the country. With my trusty iMac and Internet access, I write and run computer codes using Xcode, do graphics and some analysis with Mathematica, read and get journal articles remotely (electronically) from a friendly university library, and write up the research using Lyx. I post my papers on arXiv (at no cost); there they are freely available, searchable, citable, and forever archived.