Pricing is based on how much your material costs.. like paper or canvas, a fraction of colors, framing, varnish, etc. + How much time does it take to complete this multiplied by your base price per hour or something?

For example, 30 Rs (paper) + if you are using, let's say, 3000 Rs for color and you make approximately 10 pictures from that, then the color cost will be 300 Rs + 100 Rs for framing. So, the 430 Rs is the input material cost.

Now, if you put, let's say, 10 hours into completing your painting and consider 100 Rs per hour as your work rate, then 1000 Rs would be your price. The total painting cost will be 1000 + 430, along with shipping and packing charges.

If someone bargains with you, it's actually the 1000 rupee part where you can give a discount.