It's worth paying a bit more for a printer that's cheap to run rather than buying a really cheap printer and then finding out that even third-party inks are expensive.
With that in mind, I strongly recommend buying a printer that uses separate cartridges for each colour, rather than one cartridge for all the colours. It can work out much, much cheaper in the end. (My own printer uses 5 separate cartridges but, at under a tenner for a full set of five, it's very inexpensive to run).
I read lots of computer magazines, visit loads of review websites and read many posts about printers here on AB. There's just one brand which constantly seems to win all of the 'best buy' awards (and gets nothing but praise from ABers). It's Canon.
So, with all of that in mind, here's what I'd currently go for:
http://www.pcworld.co.uk/gbuk/computing-accessories/printers-scanners-and-ink/printers/canon-pixma-mg5650-all-in-one-wireless-inkjet-printer-10028966-pdt.html
If you're prepared to have all of the colours in a single cartridge though (and risk paying more in the long run through higher ink costs), this would be my recommendation:
http://www.pcworld.co.uk/gbuk/computing-accessories/printers-scanners-and-ink/printers/canon-pixma-mg2950-all-in-one-wireless-inkjet-printer-10122395-pdt.html
All of the above assumes that you want to do 'normal' amounts of document printing and some occasional good-quality photo printing. My recommendations would be different if, say, you wanted to use the printer in a busy office, printing hundreds (or thousands) of sheets every day.