Do a price comparison check on the web to find what deals are out there first. I managed to get the Wii Fit (on its own) from Argos and I know that they are still in high demand, although more available than before.
Yes I would recommend it, as its fun whilst toning, although there are some things that you need to over look- like the weighing part - just use it as a guide, not as scales as I do mine in the lounge on carpet, so not really effective!
Another thing is take it easy to begin with as there are so many Wii Fit related injuries at the moment (I've had one too!) like "tennis elbow".
Like all exercise though, its only as effective as you want it to be and you have to be committed too.
Hope this helps?!