hi - i use cheap close-up lenses on my 18-55 kit lens and get some quite nice results:
feeding time by
alexharrison101, on Flickr
bee by
alexharrison101, on Flickr
white on blue 2 by
alexharrison101, on Flickr
so sometimes all it needs is patience and holding your breath...(!). obviously a dedicated macro lens is best, but don't give up on what you can achieve relatively inexpensively.