Dummy Articleship is basically when you get registered under a CA for the mandatory training period of 3 years under the CA course but you don't actually go to the office for training. Two things:
Students generally take dummy for a couple of reasons.. Most of them in case they clear group one.. to have the articles period started as we as to have a sufficient study time. Secondly, if they are pursuing CA just for the sake of having a degree. Thirdly they actually wants to do CA work but currently they focus on Clearning CA final Exam.
Further, if you're anyways doing it, a CA would generally charge you for taking you as a dummy trainee under him/her, the range for which varies from City to City. Smaller the place, lesser the amount. Say monthly 500 to 2500 or a lump sum 15k to 40k.
In any case noonce recommends you to take dummy.