Who do you need to see to find out if you can just use a liability wavier or have to buy insurance for a small business?

A business scan not waive it's own liabilities.

If you are wanting to avoid buying liability insurance you would need to request that each of your customers waive your liability before doing business with you.

Depending on what type of business you have, such a request could dissuade many potential customers from doing business with you, as it would likely give the impression that your company is unprofessional, incompetent and or irresponsible.

Can you imagine a company offering to provide a product or service to you, but first asking you to sign a liability waiver which states you will not hold them responsible if they steal your money, burn down your property, perform poor work that later has to be redone or falls apart the day after, etc etc. It might be unrealistic to expect many customers would agree.