My standard answer for a cheap entry point is the Pentax K-x. Class-leading high-ISO capability, 720p video, great compatibility with legacy (read: cheap) lenses, uses AA batteries (a plus in my eyes), reasonable build quality for the price.
The K-x is available in three different kits... 18-55, 18-55 + 50-200, 18-55 + 55-300. Obviously the 18-55 is gonna be the cheapest. As for the price difference, my comparison was based on US prices... don't really know what it's like over there.
The D3000 is a very capable cam, but it lacks several things in comparison to the K-x:
1. High-ISO capability, aka ability to shoot in low light w/o severe image noise
2. HD video recording (doesn't matter to some people; matters a lot to others)
3. Compatibility with older lenses (older lenses, both AF and MF, are cheap and often great quality--the K-x works w/ all Pentax lenses dating back to the 50s, while the D3000 can only work with AF-S lenses, made since the late 90s)
You can do a side-by-side comparison on dpreview between the two.
As for lens prices... good ones are definitely $200/200GBP and up.
Well, the main things you get from more expensive lenses are:
1. Wider max aperture, aka f-stop. Most kit lenses start at f/3.5 or f/4 and have a variable aperture, meaning they're f/3.5 at 18mm but f/5.6 at 55mm, or something. "Pro" zoom lenses tend to be constant aperture (usually f/2.8 or f/4) throughout the entire zoom range. This makes it easier to keep consistent exposure across the zoom range. A wider aperture also has other advantages, like shallower depth of field (subject "pops" from the background) and better usability in low light (wider aperture means more light is entering the lens, so you get faster shutter speeds at wider apertures).
2. Better sharpness from max aperture. Most kit lenses are soft at their widest aperture and only get sharp (if they get sharp at all) at f/8 or so. Pro lenses tend to be sharp from wide open and get razor sharp as you stop down. Sharpness isn't everything, but it's something most shooters want from their gear.
3. Edge-to-edge sharpness. As above, this isn't everything, but kit lenses tend to be sharp at the center and quite blurry at the edges--simply poor optics due to corner-cutting to maintain a lower price. Pro lenses tend to have better sharpness across the entire image.
4. Build quality. Pro lenses are built to last, generally of metal vs. the cheap plastic used in kit lenses.
There are exceptions to all of the above--there are some "pro" lenses that are little better than kit lenses--but this is where review aggregators come in.