How do I know what clubs to buy

I was hoping someone could shed some light on how I decide what clubs to buy?

Rather than a list of clubs, I was after some help on how to come to the final decision. Its not like I can go and play a round with each set i have in my list and I am not a good enough golfer to know what clubs best suit my swing and skill level.

Any help would be greatly appreciated

I would do as Jonny P says and go down the secondhand route, will save you a lot of heartache and money.

First stop is American Golf/Nevada Bob's/Direct Golf.  Just browse through everything in your price range without hitting anything and without any 'help' from the sales staff.  For the ones you think you like the look of, put the 6 iron in the address position, see how it looks and then do a couple of slow half swings.  If you like the look/feel, they stay on your list.  Some you won't like the look/feel of so strike them off. 

For those you like (it will probably only be half a dozen), go back another time and try the same club (usually 6 or 7 iron) from each set.  You will hate a couple as soon as you hit them but you will also find yourself just wanting to hit a couple of them and leave the rest alone.  Then it's down to which of the final favourites you find yourself drawn to.  Don't worry about brand names or write ups.  You are an individual and you need to get what is right for YOU.  Don't let a sales person try to convince you to take something you aren't keen on (especially applicable to Adams, Hot Blade and to a lesser extent John Letters if you're in Direct Golf!).

All I will say with regards to buying new instead of second hand is that if you are not standard height/build/hand size/arm length/swing speed then getting them fitted will be a real help.  If you're Mr Average, the standard second hand sets will be fine. 

You wouldn't go far wrong with CG7's (yellow ones) Drew, Cleveland have always produced excellent clubs have owned a few sets over the years and these are no exception.They look like a proper golf club which is important to the eye's and are very easy to hit and will get the ball up in the air , the price is very good as you've mention. Try and find a golf range that allows you to test them far better feedback watching the ball flight.Good luck.