<p>Well for Science, the following programs are free (however rather difficult to get into):
Research Summer or Science Institute: Research based summer program in which students get help from scientists in the boston and cambridge area to do research projects. Held at MIT.
Summer Science Program: I don’t know too much about it aside from the fact that students take rigorous classes and take part in a final project having to do with astronomy.
MITES: Program in which students take rigorous courseload for seven weeks. Also held at MIT. Geared towards underepresented minorities.
WTP: Engineering Summer program open only to highschool females. Once again held at MIT.</p>
<p>I know much less about Humanities and Writing based programs but I hear TASP is good and so is LEDA (although it’s mainly for minority students).</p>