Another alternative is to go to Poly for a year or two and take care of some general requirements. Then, transfer to MIT. Schools are generally very receptive to transfer students who they originally admitted in the first place, especially if you explain that the decision was financial.

Also, just a note - I'd advise you to be wary of the advice you get. Few people have attended both MIT and Poly are able to directly compare them. The opportunities you will find at both schools are simply different, not necessarily with one being better than the other.

MIT will certainly have more resources and opportunities than Poly. However, keep in mind that there will also be more smart, motivated people vying for those opportunities, and in reality there is a fixed number of opportunities you can realistically pursue anyway.

But Poly will allow you to stand out. In a place where few of your peers will even bother to speak to the professor after class, you can monopolize on the opportunities that are available. Plus you will always be seen as "that guy that got into MIT," and your peers will view you as a leader, allowing you to take leadership positions and convince other people to join your projects with ease.

Also, don't underestimate the magnitude of the money you will save. 100K could be the totality of savings you will amass 4-5 years out, graduating from MIT. That's a lot of time to grind away paying off debt.