The prices vary depending on the quality of the mice offered (i.e. the better they are the more people are likely to want them), the poularity of the variety and how many people are interested. I have heard of trios going at Enfield for as little as £3 but at Harrogate (a big show) they have gone for over £50. I doubt anything at Enfield would go over £30 a trio though. As for when it starts, it varies but usually mid-afternoon.