I took the NCLEX-RN in February in Arkansas. I think it was $200 but I think they went up after I applied to take it in September of last year.
You pay the same amount no matter where you take it, I think. And it's standardized, so there's not a state that you can take it in that's easier. I believe the passing level is also standardized as well, so you have to attain the same level to pass in Mississippi as you do in Arkansas (just an example).
What differs is how many times a state will allow you to take it and how long each state will let you work as a GN on a temporary license. I'm licensed in Louisiana, and you can work for up to 90 days after graduation on a temporary license before you take the NCLEX. If you don't pass the first time, you cannot work as a GN, you can only work as a CNA (or as an LPN if you were licensed previously as an LPN and the license is still current). If you don't pass the second time, you can't work as a CNA unless you become certified officially (going to nursing school
doesn't count). If you don't pass the third time, forget it, you're not going to be a RN.
Mississippi, on the other hand, is a little different. They don't have a limit on the number of times you can take the test. So if a GN in Louisiana cannot pass on two tries, he or she might decide to move to Mississippi and keep taking it till he or she passes, then transfer his or her license to Louisiana. Perfectly legal.