United's costs on Sat to Sat round trips from Chicago to the Caribbean have been over priced for a long time. Just because they fly non-stop to most destinations there, they charge a premium of 30-50% over their competitors.

For the $1000 United was asking you could fly in First on American. We usually fly on American out on a Friday evening, over night in Charlotte and get the first flight to SXM the next day. Coming back, we usually connect thru MIA or CLT. With Global Entry, it's easy to clear customs at either location. You could also connect through PHL, but I dislike connecting at northern airports in the winter.

Take a look around. There are definitely other options to United.