Let me start by saying that I have seen numerous adaptations of "A Christmas Carol", and I have read the book, so I know the story inside out. This is, without a shadow of a doubt, the worst adaptation I have ever seen. I love musicals, but I could not get through this. I absolutely agree with all the other reviewers about the acting and the songs - both are terrible.
Even though it costs £2.99 (+ p&p), it is just not worth it, so take my advice and go for one of the better versions, such as "The Muppet Christmas Carol", "Scrooge (Albert Finney version)", "A Christmas Carol (George C. Scott version)" or "A Christmas Carol (Patrick Stewart version)" (I have not seen the Alistair Sim version, but I plan on watching it this Christmas).
EDIT: OK, I watched the Alastair Sim version last night, and it was brilliant!