where to get cheap general liability insurance for my business?

Your best bet is to find an independent agency. They write for multiple companies and can do a lot of shopping around for you. It also helps that you've got an experienced, local professional to ask questions. I think this is especially important for commercial insurance since it isn't nearly as standardized as personal lines and it can really help to have a conversation about what you actually need rather than plugging things into a website for coverages you don't know anything about.

Depending on what services you'll be managing, you may need:

General Liability (clearly)

Commercial Auto (if you have work vehicles with branding)

Inland Marine (for specialized or expensive equipment)

Cyber Liability (if you'll be managing IT work and/or maintaining sensitive client records)

Errors & Omissions (if your business also serves an advisory role to clients. e.g., financial advisors, insurance agents, etc.)

Commercial Umbrella (not strictly necessary, but always advised)

There's a lot that goes into commercial insurance and it isn't something I'd take an "I know best!" approach. Just like taxes, there can be a lot to navigate. Risks are so individualized, that a company which is good for one person might not be for you.