@biochemgirl67, I too thought 4.2 was magically greater than 100%, but someone informed me that some schools give a 4.3 or 4.2 out of 4.0 for an A+; whereas a 4.0 is “only” an A.
As to the question, the prestigious name is not worth the extra money. The increased efficiency of gaining experiences with the available resources may well be priceless, IF the student really takes full advantage of the programs, people, and equipment. Prestigious schools are prestigious for a reason, and that is usually because the teaching and opportunities are better. How much better? 10%? Who knows. If you need to conserve cash, look at the long view. Realize that undergraduate can feed your trove of knowledge, or it can be life changing. If it is life changing, it may be worth paying full freight. You will not know in advance. And who’s to say that “B” grade schools will not offer a life-changing experience to a specific student?