A typical bachelor's degree in engineering involves no more than 5 courses per term for 8 terms. Discard the wasted 1 course per term of humanities or other irrelevant drivel, that leaves 32 courses total, each of which consists of little more than learning the contents of one book. Look at a college catalog and degree requirements, figure out what those 32 books are, buy them and learn the contents. Buy a computer and teach yourself enough programming to be able to handle some problems in your field, also learn some of the standard software in the field that's freely available (or available as student edition), like SPICE. You are now short of a college education's "well-rounded rich engineering base" only by the absence of some lab courses.
About $4000 plus room and board for the time it takes to learn the material, some hands-on experience, done. As a bonus, no exposure to depraved fellow students.