Well, I would thoroughly recommend the M-Audio Luna. Large Diaphragm condenser mic.
It`s versatile, but very good for vocals in particular, having a nice warm vintage sound, and is on a cheap offer at turnkey.co.uk

If that is over your budget (£100)
Then go for the shure SM58

As for sampler?
Well, I would suggest an audio editor, such as soundforge or wavelab, to process your samples.

And I would suggest a package such as Fruity loops, initiallly as it has built in sampler/sequencer and audio sequancing capability, and works from beginner evel to pro fairly well (as a lot fo people here would attest to)