Most bedroom DJs will end up spending an awful amount of cash on amps and speakers if they are not willing to invest in decent equipment at the beginning.
When I first started Djing I was on a budget so had to stick to a relatively cheap do it yourself set-up.
This ended up costing me a lot in the end as I would always blow my system.
Not having a proper understanding about how to use the graphic equaliser and playing amps at a louder wattage than the speakers can take is a very common mistake amongst bedroom DJs, I know I went through my fair share of systems when starting out.
As a general rule of thumb when buying a system you should always make sure that the speaker wattage matches that of the amp.
Also it is recommended that for the best possible sound quality the speaker cables for any stereo system should be at least 10% of the cost of the overall system.
therefore if your stereo system cost £1000 at least £100 spent on speaker cables would result in a much clearer sound.
I would also recommend purchasing a good strong and reliable set of needles, quality needles is a must as most bedroom DJs love to practice scratching but are very heavy handed on the turntables.
Which usually results in the needles snapping.
Also having a spare pair of needles is always handy, there is nothing worse than a needle snapping when you are half way through a set.