I did quite a bit of looking around, when I was fitting my own CCTV system and I researched the things that mattered - camera quality, HDD size, etc, as I was virtually clueless as to what I was after.
Anyway, just had a look on Ebay and found this, a bargain in my opinion:
http://www.ebay.co.uk/itm/1TB-Hard-Disk-8CH-720P-AHD-DVR-4X-2000TVL-960P-Camera-CCTV-Home-Security-System-/272457785029?var=&hash=item3f6fbfdec5:m:mRcw5o05wi7ukx119Fh9-0w
It includes 4 cameras and it's an 8 channel system, so you can add more cameras if you want. The cameras are 2000 TVL - basically they're HD quality. It also has a 1 TB hard drive - probably enough room to store 2 weeks of 24/7 recording on all 4 cameras.
It's roughly the same price that I paid for mine, but mine is only a 4 channel system, so I cant add more cameras to it, although to be honest, 4 is enough.