How can I advertize for my new small service based business?

I’m starting a small business where I’ll go out to people’s homes and help them find ways they can make their home more eco-friendly, while saving a few bucks on their utility bills. I’ve got some training in this and have plans to get certified as well. After all this, I’ve never started a small business, so I’m not sure how to get my name out there, ideally without spending a heap of money, at least to start. Any ideas?