The best places in the UK are: http://www.pullum-sports.co.uk
Spend the money now so you dont have to later when things break or stop working.
Cheap equipment will cost and annoy you in the long run.
Buy an olympic bar (20kg empty,
Nickel is best),
some olympic adjustable dumbell handles and a set of plates 150kg in total.
you will also need some good collars especially for the dumbells.
Buying a set of dumbells is really expensive!
If you are benching at home I strongly suggest getting a safety rack from pullum,
it costs about £600 but could save your life!
check youtube for videos of people who bench at home with no spotter or safety rack.
and bear in mind they are the ones who survived!
Hope that helps and good luck!