To reiterate ...
If you are using it for commercial use, then you will need to get a BOP (Businessowners Policy). A BOP has two parts but they are combined into one: liability coverage and property coverage. The liability coverage typically starts at $1,000,000 and this protects you from lawsuits because of injury caused to others by your actions. The property coverage is exactly what it sounds like as this will cover your business-related properties, and this generally has a $500 deductible attached to it.
Obviously this will vary greatly by country, but this also varies by state. The $755/year that
@mw174620 quoted sounds about right. Some companies will have a minimum premium of $1000.
Edited to add: As for the umbrella policy for personal use, that's nice to have for extra protection but is not required to get personal liability. A typical homeowners policy or renters policy already has personal liability built in to it. Basic is $100,000 liability, but you can up it to $300,000 for about +$25/year. An umbrella policy will add another $1,000,000 liability protection on top of that, and it runs about $150/year. In order to get an umbrella policy though, most companies require that you have at least $300,000 in underlying liability coverage in your homeowners/renters policy. In addition, you generally need 250/500/100 or 300/300/100 underlying BI/PD liability coverage in your auto policy to qualify for the umbrella but most people only have like 25/50/25 coverage.
I am currently a Software Product Manager, but I worked as an insurance agent for almost 3 years.