Hi.
There is a lot of information on here about stage 2 and how to prepare. I can't remember how much stage 2 is these days, £150/250? How will you pay for this, furthermore, the course itself if you can't afford the skytest (or whatever its called). Don't mean to be rude, just a genuine question?
Regardless of that the best way to prepare is to do lots and lots of mental maths. You can create a similar test environment at home by practising spatial awareness and logical thinking problems, spotting patterns etc at home. There must be books that have pages of these type problems. Wish you the best.