GEL my sister cannot remember how much she paid for her monthly lenses but said it wasn't much, she did get them in Kerala though and glasses and lenses and cheaper still there.
I did try having prescription sunglasses and normal glasses when I went to Egypt about 6/7 years ago but found it a pain in the neck having to keep changing my glasses over and carrying around another pair of glasses when I was sightseeing and juggling the camera and camcorder as well. I don't find I have a problem with seeing again when I go back inside from outside. I have been going to hot, sunny countries for over 40 years and don't find it affects my eyes or I have a problem with my glasses, but I suppose we are all different, we have to do what we think is best for ourselves.