Jamie,
Another thing to think about is doing the MCC on a jet sim, instead of a FNPT II sim thus getting a kind of JOC included. For example, I did my MCC on a 757-200 Cat D sim. It was just over £1,000 more than doing it on a fixed base sim. I reasoned that £1,000 divided by 20 hours was £50 an hour to get a shed load of proper sim experience.
Callsign Kilo correctly points out that you could always hire a sim for a couple of hours, but that will also cost in the region of £1,000 - and you only get 2 hours.
When I had my first sim assesment I was in a much happier place because I had some idea of what I was going to be up against, how the aircraft handled, and what the sim itself was like - it made a huge difference, and I am now lucky enough to fly the B757 for real.
I also hugely enjoyed the MCC, loved the full flight sim experience and gained an awful lot from it. Don't think it's impossible fail, and treat it as a very important first stepping stone to flying a multi crew aircraft - it's completely different to what you are currently used to.
DW.