buying online means you miss out on huge discounts.
the standard practice is to use sapphires - decks.co.uk and another company, I use and prefer JB's.
Ring up one anf get a quote for your desired equipment, take the guys name.
ring up the rival firm and tell them about your quote, get their offer and again take the guys name.
ring up the first company and do the same. When they cant beat the price start getting them to throw stuff in for free, carts, styli, a record bag - these usually come as standard with a set of turntables, so try and get them upgrades to better ones.
Personally I will never buy any equipment off sapphires again, after getting some faulty speakers at christmas from them, returning them was a nigthmare and straight away they blamed me for the fault, they also exaggerated the damage when they recieved the goods.
playing them off against each other can get big discount, I got 2 cdj800s for £800 when they retailed at £500 each