You may “alternative” channels surprisingly cost-effective. Reach out to semi-popular youtubers aNd bloggers in your industry - they may promote you for a  relatively small fee; check out your local radio rates - it’s often very affordable; looks for advertising at smaller networks like meetup, wordpress, Pinterest, even Twitter; write comparison/review articles for products in your industry- they do really well in organic search engine positioning. If you have to advertise on Goog/FB - prepare to pay a lot to Goog but you’d have real visitors; while FB is most likely to look cheap but won’t product any real traffic to your site ultimately - it’s only good for gaining likes and selling cheap nifty gadgets.