>Could you advice me how much cost $1M liability insurance policy?

Personal or Professional?

For personal:
In the US, you can get an umbrella liability rider (essentially an add-on) for your homeowners policy for $1M. About 10 years ago, I had one of these and it cost me less that a couple hundred bucks annually. Haven't looked into it recently, but it will depend on your claims record, however.

For Professional:
Around here, you can purchase $250,000 worth of professional liability insurance for around $3,000 annually. It went up from there, and I think it depended on your business activity level (number of customers, sales forecast, etc.). And I didn't look beyond $250k for my purposes.

Just throwing this out for conversation, of course. Check with an insurance agent for more current numbers that apply to your specific circumstance.