Not the same thing, but a drone and possibly an alternative if you have an electric guitar is Electro Harmonix' Ravish Sitar effect pedal. I have one and I'm very happy with it. It has two outputs, one for lead and the other for the drone. In order to switch back and forth between lead alone and lead and drone, I had to buy an AB/Y pedal (from another manufacturer), which cost about 10-15€. I think this is a design flaw, but I can live with it. Of course, you can also turn off the lead and have the drone alone. The Ravish Sitar pedal currently costs 219 € at Thomann.

(I don't have any financial arrangement with EHX, Thomann or any other store or manufacturer.)

Thomann also has Shruti boxes from 220 to 350 € in price. They come in male and female varieties. You can save some money by buying one of each and leaving them in a room alone together.