Most exams are $185, though it varies a little. Check here: https://www.excelsior.edu/portal/page?_pageid=57,194513&_dad=portal&_schema=PORTAL&DEPTS=EXAMS&AREA=A%26S&SORT=0 I haven't taken enough of them to say which are the easiest. I found College Writing and Psychology of Adulthood and Aging to be the easier of the ones I've taken. Time varies per test as well. Take a look at the guided learning packets (pdf's) on the Excelsior website. They have a good deal of info on the tests as well as practice questions.
I took the English Comp exam (434) 1 month - 1 day ago. It cost me just under $300 for the 6 semester hour exam. I had to drive 1 hr. 30 mins to the nearest testing location for an 9:00AM exam time. I was done before noon. I found the instructions/expectations unclear. Even so, it was about as difficult as a "butt-in-the seat" exam at xyz state college. The exam required that I read a short work and then write an easy about what I read. It did this three times. One of the examples was from a college admission letter which I was to critique -- I wanted to write "this kid should finish high school and then go to a community college before he comes to the university..." but I didn't. Another example required I write on Updike's A&P while the other was on Chopin's The Story of an Hour[/I]. My issue with this particular exam? It's been over 30 days and I don't have a score yet. I hope that's a good sign but expect it's simply common experience with this particular exam. I took the nursing exams by ECE many years ago when I was in the field. They were relatively easy exams if you know your stuff. Otherwise, my testing experience has been CLEP and DANTES.