http://www.telegraph.co.uk/gardening/8822843/How-to-buy-the-right-greenhouse.html has a lot of sensible advice. Coupled with real experiences from our goy members might help you make a decision. Our own 6' x8' was given us by a friend who was upgrading to a larger one. We have a 1' high wooden base. It sits on a concrete base and in spite of treating the wood it has deteriorated over the 25 years or so since we got it. Some of the glass was replaced with non safety glass and I would not have that again because it shatters and makes a dangerous mess. Given your budget I would choose a larger aluminium greenhouse over a wooden one but if aesthetics are more important compromise on the size and choose wood. If you do choose wood I would recommend a base built from brick so that you can more easily grow in the borders. I'm sure you will get lots of advice so happy choosing you lucky lady.

If you want a good looking building, then wood. If you want a practical, low maintenance structure then aluminium. Also, you would get more for your money with aluminium.