Hello, first off, welcome to the forum
I have taken both pred and entocort. Prednisolone is a systemic steroid, so it treats inflammation anywhere in the body, which is why it has such a wide range of side effects. Entocorts is also a steroid, but it only treats inflammation in the intestines, so it generally has fewer side effects, but it is thought to be less effective at treating inflammation in the deeper layers of the bowel wall. Also, entocort will generally take a couple of weeks to start working to a level where you feel the benefit, so it is important not to get disheartened if you do not get the instant relief that many report in the first few days with pred.
I live in Wales in the UK and my medication is free, so I cannot help with costs, but i'm sure someone who can will be along soon.