Firstly, there's nothing wrong with the 18-55mm Nikon kit lens. It will do everything an amateur needs and more, though macro work is rather specialised.

You will find it very hard to find a new macro lens within your budget - most start at around $400. You might consider investing in a set of good extension tubes instead, which will let you use the kit lens as a pseudo-macro lens.

Extension tubes are simply hollow tubes that fit between the lens and the camera. The math is somewhat complex, but essentially this allows you to get much, much closer to your subject. So they essentially turn a standard lens into a kind of macro lens. They usually come in 3 sections, which you can attach in any combination for varying levels of magnification.

You can get very cheap ($20) extension tubes that are just tubes with lens mounts, but you lose aperture control, metering and autofocus. More expensive tubes have the electronic contacts which allow the camera to communicate with the lens, as well as aperture control mechanisms, so you can use the lens as normal.

Your other option is macro lens adaptors. These are essentially magnifying glasses that screw onto the front of the lens, with obvious effects. The quality of the image tends to suffer a little with these, but they are a more affordable alternative.

It really depends on your situation: if this is your first SLR, then I'd recommend you take the kit lens, which will let you experiment with everything from landscapes to portraits and help you decide what kind of photography you like; there's no point in diving straight into macro only to find you don't really care for it.

If, however, you have your heart set on macro then I'd either look at second-hand Nikkor lenses or save up for new versions of the same. Always try out any new equipment where possible to make sure it suits your needs.