My first thought was to recommend the double major because I believe that a stronger math background opens a lot of doors, specially in the software industry.

My first thought was to recommend the double major because I believe that a stronger math background opens a lot of doors, specially in the software industry. Now, considering your last statement and the fact that you also have a minor in economics I'd say you're better off saving those 50K and extra year. Getting involve in open source projects it's a much better strategy to differentiate yourself that getting a minor/major, at least in the software industry. Good luck!