If you bought turntables chances are your going to have to buy cartridges for them. Cartridges cost anywhere from $20-$100 and replacement needles for them cost a little less than half of what the cartridge costs. If you do a lot of scratching your going to want a cartridge which has good scratch resistance and a low tracking force (so you don't ruin your records). Club and dance DJs would most likely prefer a cartridge with good sound quality. In addition to normal cartridges that mount on the turntable headshell, there are also concord-style cartridges which screw directly into the tone arm. Concord-style cartridges are mostly used by dance DJs.
