I've also been looking for a shed, if you want a new one then the cheapest one that looks like it will stand up to a bad winter is at shedsworld (on the website), prices there include everything (so wooden floor as well as delivery).
If you're bargain basement gardening like me, I've got an eye on ebay for local sheds (ones that you have to take down yourself), and will start looking september ish for some ex-display models at the DIY superstores and garden centres. If you're oop north, JTF have a shed that's just over £100, but it does look as though it would fall down if someone trumped on it!
it is said that you are never more than 6ft from some kind of rodent ,so under decking and sheds would be there prefered run.
I reckon that the idea of timber decking was more or less force-fed to us a few years back via one of those TV "make-over" programmes. Having seen quite a number of gardens where this has been installed, I've come to the conclusion that - on the whole - it's not a good thing to have.
It might work better in countries where the weather's better/drier, but here in the NW it can get so slippery in wintertime/wet weather as to be positively dangerous! If it's not installed properly (i.e. with gaps to allow for expansion) it tends to move a bit, and if you do have the necessary gaps, these allow for all sorts of stuff to fall through them - "lost" jewellery was one example I heard about. I'm sure it needs far more maintenance than you'd think - and I wonder whether it'd last long anyway. It does provide shelter for some of the unwanted garden visitors too - and although here in the UK we'd not get a possum living underneath (as was the case in my D's garden - she lives in the USA) I bet the rats love it. So - not for me, under any circumstances!
I think decking has it's place. For gardens that have a steep slope, it can be great, as it's a quick, easy and relatively cheap alternative to putting in terraces. However, I agree wih hyper that it has rather been force fed to us and is now the thing to have. My SIL has it, and I do think it looks a little bit daft, the garden having a very gentle slope. On the good side, when it's a nice, sunny day, it's warm on bare feet, unlike any other 'patio' surface. I don't have it in my garden, I'm lucky enough to have a flat garden, had I got a sloping garden, I'd consider it (but only as a stop-gap to putting a more permanent terrace arrangement in). Each to their own, but I do wonder how many of these deck areas will still be around (and looking good) in 20 years? I remember my parents putting a patio area in (I won't say how many years ago, but I was just a kid then, and I've children of my own now), and that's still there (or was before they moved out to Spain. So personally I'd be saving and putting a sandstone or slate patio down!
ian, if you are going to put down slabs I would give some serious thought to preparing a proper base unless you are willing to relay them every few years. to do this use DTp1 sub-base (often called type 1 scalpings) from a builders merchants (roughly £25/tonne). A tonne covers 6-8 square metres. You need to lay this about 3 inches deep and compact to around 2 inches with a wacker plate (which you'll need to hire). You then lay your slabs on cement on top. You can use the compacted scalpings as a base for your shed without the slabs if desired.
This probably involves more cost and work than you want, at least initially, but over the years I have come to the conclusion that laying slabs without a firm base is a total waste of time.
I agree with Paul's comment on a 6 x 4 shed. Get the biggest one you can afford, but at least 8 x 6. For a quick base use a couple of pallets if you can get them!