Most entry level DSLR cameras optionally come with a disposable lens. It is called the kit lens. It is generally bundled for under $100 more than the camera itself. Invariably, it is a zoom lens made of low-quality optics designed to get the new buyer started with his digital camera right away.
Notice how there are barely any new lenses which can be bought for under $150? That is because even mid-quality optics cost more. A great exception is the Canon 50mm F1.8 II lens. Since DSLR-kits are designed for entry-level users, cost is very important. To keep within those costs, camera makers generally choose poor quality optics. The exception here comes from Panasonic which uses a 14-50mm/F2.8-3.5 lens with its Lumix DMC-L1, producing one of the most expensive DSLR-kit available.
Even if the image quality of a kit-lens is acceptable, which depends on the medium and the user’s eye for detail, these are generally not versatile lenses. The minimal kit lens is an 18-55mm lens for cameras with a 1.5X or 1.6X focal-length-multiplier. A few camera makers offer an 18-70mm lens instead. Here Nikon stands out with a 18-135mm lens bundled with some of its latest DSLR cameras.
Generally, not only do these lenses have a short zoom ratio, they also have narrow maximum apertures. The Sony 18-70, for example, is quoted at 18-70 F3.5-5.6. In practice, the maximum aperture drops very fast: F4 around 20mm, F4.5 around 24 and F5.6 already at 35mm. This means that more light is quickly required as you zoom in. It also causes the camera to focus more slowly, particularly near the telephoto end of its zoom range.
The conclusion is simply that kit-lenses are disposable. Even if a kit-lens serves a temporary purpose for someone who cannot afford something better, a replacement should eventually takes its place. If the short zoom range is sufficient, a much higher-quality lenses can replace it. If the zoom range is too limited, a long-zoom ratio lens can be purchased instead. Perhaps the latter option won’t increase image quality, but it will improve versatility. There is always the option of getting several high-quality lenses to cover a wide range of focal-lengths to achieve quality and versatility. In other words, it is easy to do better, but nearly impossible to do worse.
Don’t confuse the kit-lens with higher-quality bundles offered by some manufacturers. The immediate way to notice the difference is price: those bundles cost quite a bit more than the camera itself. Also, such bundles come with one or two lenses which are readily available for purchasing separately from the DSLR.