please tell me where i can find small lasers for cutting of hard stones in low cast?

Answer 1

A $1000 laser has about enough power to cut paper.
A $10,000 laser will cut plastics.

For perhaps $10,000,000 you could build a laser to cut hard stone. Lasers are not very good at cutting stone.
There are dozens of other ways much easier, and for very low cost.

Answer 2

Low powered lasers can't cut stones and you need high powered lasers which are expensive.