What is the cheaper alternative Nikon lens?

I have a Nikon D5000 and want to buy a cheaper alternative lens that can go from 18mm to 300mm (or something).

I use my camera to take pictures of people and events (for fun, no clients). I hate changing out lens (long to short, short to long) because it's inconvenient when you want something up close one moment and then far away another moment (like taking a pic of a huge group of people at a party).

I can't afford another Nikon lens, so what is the cheaper alternative I should buy and what quality am I sacrificing?

NONE

There are NO 18-300 mm lenses made by any lens maker

You can buy the very fine 18-200 mm Nikkor lens and sell the 18-55 mm lens you have now.

Just so you know, the 18-55 mm lens really does what you need when shooting a party. At 18 mm you can take fine group shots and at 55 mm, head and shoulder shots.

Just use a flash diffusion filter on your flash.

You should go with Nikon 55-300mm f/4.5-5.6G ED VR AF-S DX Nikkor Zoom Lens for Nikon Digital SLR

5.5x Telephoto Zoom lens
Nikon VR II Image Stabilization; Tripod Detection Mode
HRI (High Refractive Index) Lens Element
2 Extra-low Dispersion (ED) Elements
Exclusive Nikon Silent Wave Motor (SWM)

Here's the nearest thing for you. Tamron makes an 18-270mm f/3.5-6.3 Di II LD VC lens that sells on Amazon for about $630.
http://www.amazon.com/...001DYC0CS/

Here's a couple of reviews.
http://www.dpreview.com/...p3_vc_n15/
http://www.photographyblog.com/news/tamron_18_270mm_lens_for_nikon/

And some user reviews:
http://www.amazon.com/...001DYC0CS/

And some sample photos taken with that lens.

Now, on the shorter end, I took a two week overseas trip with one Nikon DSLR body and a Nikon 18-200mm AF-S VR in 2007. Frankly, it covered most situations very well.

My one concern for the Tamron and any other long-range zoom (I have a Sigma 28-300mm that my daughter used on the same trip) is the f/6.3 on the long end. You'll lose some shutterspeed flexibility and may be challenged when the lighting is less than optimal.

If you want a super-zoom, then go for the Tamron 18-270mm. It is currently the longest super-zoom ever made. On the pro side, it is very convenient and suits you as you hate changing lenses. But on the other hand, you are sacrificing many aspects. With this type of lens, manufacturer sacrifices image quality for price. Also, at the tele end of the lens (270mm), the aperture opens only to f6.3, and at this point, it is not a really fast lens. So I would recommend you to get separate lenses and get use to changing lenses.