I was reading an article about the extremely cute and clever Australian business Babybuds (those flowers are actually little singlets and jumpsuits!). As with all new businesses, they had little money to spend on marketing in the beginning, so they focussed on zero budget marketing ideas. One of these was looking for online communities or information websites where they could get a free listing.
Whilst there's a plethora of baby and kid information sites, there's also more than 100 million sites on the web. So start looking for ones that might provide a free listing for your business!