Unassailable1991:
It really comes down to how much the funds matter to you and your current situation. If the gap is not too sizeable (and it's not clear what the total cost is for Marshall that you're estimating), you're always better off with the better known, higher-ranked program. The quality of alumni, job opportunities, available resources, etc. will be theoretically better and are thus part of the value of the degree.
If you want to look at this way, do you want to get a free $50 item or $50 off of a $100? Will the $100 item last longer? Will it bring your more happiness? etc.
It's not an easy decision at all, but our advice would be to take Marshall for the long play.
FYI, you just might be able to go back to Marshall and see if they can close the gap between their offer and what MSU and GT are offering. They might not match but could offer you more money. You never know...
Congrats and good luck in your decision,
Admissionado