My neighbour wants to sell his car maruti 800 model 1999.I want to buy

Is that 5 speed?

Let me tell you, the pricing is depended on the condition of the vehicle. The tyres, battery, paint, inside of the car, insurance, tax and so on stuffs.
It is better if it has LPG and music system and all.
The current market price of the 1999 model Maruti 800 is Rs. 40,000 to 70,000. Even if the car is in great condition with LPG and music system, a deal of Rs. 60,000 - Rs,65,000 would be fine.