The Numark NTX1000 is quite similar to the Technics SL1200 and even has a similar headshell. Any half-inch mount cartridge should work well. Phono cartridges sold in the Indian market (brick and motor stores) are heavily over-priced. With an average budget, a lot of cartridges can be bought from abroad in good condition, inclusive of shipping. At entry level, models from Shure, Stanton, Ortofone, etc are the staple. If you are on a budget, then cartridges from mainstream Japanese manufacturers like Sony, etc are quite reliable. The Shure range is quite wide and they cover the different price points. The Shure M70b, M75series, etc are staple budget carts which produce very high quality sound. Then there is the legendary M44-7 which is a good buy but prices these days seem to have gone through the roof. On the hire end of the Shure spectrum is the V-series. Try ebay.de and ebay.co.uk. Also helps to drop a note in the wanted section of our forum.