I'm surprised I haven't seen any posts about hammocks. Very lightweight and easy to put up.
I have one of these:
http://www.ddhammocks.com/product/dd-frontline-hammock £44.99. Built in mossie net. You will need a tarp - I made my own. Adding "Whoopie Slings" (stop sniggering at the back) is also a good option. I made my own - DD sell "Amsteel" in metre long lengths for this.
DD Hammocks are great on quality and delivery. There are other companies ie Hennessy which also get great reviews.
Now I bought one of these years ago
http://www.handyhammock.co.uk/order They are expensive - I bought mine about 7-8 years ago. I have used it on sandy beaches as I have sand pegs (optional). Be prepared to answer loads of questions when using it! Last year I modified this to be able to take the DD Frontline.
I also made a stand for in the garden, cost around £50 for the timber and hardware. A great way to spend a Sunday afternoon when the sun's shining and you have a muzzy head from the beers consumed the night before
Please ensure you learn how to attach them to trees properly. Not just so you don't fall but so as not to cause any damage to the tree.