I'd also chime in that it's often not a good idea to buy a prebuilt machine from a shop. As you can see in Mick's posts they're asking a lot of money for a machine that if you bought the individual components yourself would cost a lot less.
They also pretty much always skimp on the GPU, which is a big no no if you want a gaming PC.
If you have to have someone else build a machine for you rather than building it yourself then the best bet are websites that allow you to pick specific components and will build it for you. That way you can see the price of the the components (and compare them to other websites) and the build price in the total cost.
Overclockers website in the UK is a good example of this (although I've found they're a little more expensive than my preferred website to buy from which is
ARIA (whom I also think will build the PC for you if you ask))
Obviously these sites won't be much good to you Mick as they're UK based but I'd recommend hitting Google and seeing what you can find similar locally to you. Spending more time now investigating and waying up your options will save you cash and mean you get a decent PC that will last you years rather than one that is out of date now.
P.S. Anyone on a budget should be looking at AMD CPUs and GPUs, generally they are a lot cheaper than Intel CPUs and NVIDIA GPUs for similar performance and I've found that motherboards for AM3+ chips are generally cheaper than Intel based ones.
Stick with 8GB of RAM for now, you don't need 16GB and RAM prices can fluctuate a lot, what might be £40 today could be £20 in a few months.
