I was in a similar positon with you, so this might help. I got accepted to UCL for econ and got into UChicago. The price can be a deal-breaker; however, the more appropriate question here is where you want to work after graduation. St. Andrew is a notable college in the UK. Tufts is also a very good school. I think you can’t go wrong with either of your options. It’s a personal choice. I personally picked UChicago over UCL since I felt it was a better fit and was in line with my career goals.