Advice on building a raised bed

 Im new to gardening and have recently moved into a rented house with a big (and slightly overgrown) garden. I cant change the garden too much but I would like to grow my own veg so I thought I would put a raised bed at the bottom of the garden but have never done this sort of thing before so Im looking for some advice  The area that Iv earmarked is paved (very uneven) with lots of weeds on it (to the point that we initially didn’t know there was paving underneath) which I’m in the process of clearing!  Can I put a raised bad on top of paving? Can anyone suggest a good quality but cheap way to build a bed and how tall should it be (Im thinking at least 2ft if I build it on top of the paving and Im thinking of growing strawberries, peas, squashes and onions etc…). Also, what sort of soil should I put in it (can I use the multipurpose compost that I use for containers?).   Any advice would be greatly appreciated! 

You would be better off growing in pots than trying to construct a raised bed on paving. You can raise all sorts of veg and fruit in pots but they do need a good compost, feeding and lots of watering. Start of with some mixed salad leaves, spring onions, strawberries, tomatoes and herbs.

With respect to Polly, I think a raised bed on paving would be fine if, as you say, it's deep enough.  But you would need to make it self-supporting or buy one of the kit-form ones. I bought one a bit like this when the local garden centre had a sale on last year (it might be a good time to look abot now!),

http://www.greenfingers.com/superstore/product_review.asp?dept_id=200486&pf_id=LS7672D

 I laid sheet of permeable membrane across the bottom and stapled it to the sides to stop the soil washing out of the bottom when watering etc, and lined the sides with heavy duty plastic.  

The person at the garden centre recommended multi-purpose compost to fill it with,  I was doubtful about this and checked out my feelings with this Board and I'm glad  I did.  The advice was to fill it with a mixture of bought top soil and organic farmyard manure - not cheap, but it'll last much longer and provide better growing conditions for the plants.  I've got fantastic crops already this year, including the best courgettes I've ever grown.