any old folks in your group?
if no old folks and are young adults that are willling to be adventurous, i will suggest get the flight that has long reasonable layover (not those layover that has flight departing at 6am) and experience another country. maybe you need to pay ~ $150 to $200/night hotel. some food expenses, travel expenses, if work out that you still are left with 1k (or any amount that you are delighted with) from the 1.8k after all that then go for longer layover.
you will have that extra 1k to use/save on your final destination.