You would be surprised at what can be achieved with quite a modest setup. Obviously, high quality equipment (ie expensive) will yield higher quality images, but the experience and knowledge of the user is a huge factor in the outcome.
Here is a shot I took earlier this year of M51 using my 10in SCT:

There is still plenty of room for improvement but it shows good detail in the spiral arms.
This image of the same galaxy was taken with a small 70mm scope that cost me $150 (factory refurbished), a $50 tripod that has a tilt plate (for polar alignment) and the same CCD camera that was used for the image above (about $500 new). The little scope could not cope with the weight of the filter wheel, so the image had to be monochrome.

A few more:
M17 The Swan Nebula using a Hydrogen-Alpha narrowband filter:

M27 using the same setup:

Jupiter:

Part of the Abell 2151 'super-cluster' of galaxies in Hercules:

and without the labels:

M13 Globular Cluster:

You can basically sink as much, or little, as you want into astrophotography. Some invest many thousands of dollars, but for most of us, much less.