4-5 years back, I had built a broadcasting equipment for fun purpose. I am mad about small scale electronic assembling (Even now I am but I don't have enough time)
How I did it:
There is a company called VegaKit that markets readymade kits with a printed circuit board(PCB) along with the necessary components such as resistors, capacitors, semi-conductors, transistors, heat-sink, etc. You just have to mount and solder the component as indicated in the circuit diagram.
I remember the kit was sold at about Rs. 150 at that time.
However, you can broadcast only in an range of 1 KM. If you use a YAGI antenna, range can be increased upto 5 KM. However, make sure that you won't be interfering any other frequency.
Don't use such equipment for commercial broadcasting. Besides that it needs a license(available for a huge sum), the equipment thus produced is not THAT high quality.
Also, if you can't get Vegakit, search for some other company that markets similar products. I am sire you will find atleast one at Lamington Road, Mumbai.