The LAME encoder is less than a megabyte in size, and the GUI I provided is about 6 MB. As for RAM, (a) it shouldn't matter, it'll just go slower if you run low, and (b) encoding audio takes barely any RAM. I can do it just fine on my Aptiva, and that's nine years old and has 96 MB of RAM.If you don't want to download a huge file and waste RAM on your computer, you can use online ones... In fact, I've been using this site for a while now:
https://www.mediaconverter.org/
Free users are only allowed 5 conversens a day, but that's enough for me.