Hi Itsy -
I'd start with a hatchet or hand axe - for light work and kindeling , a 2 1/2lb felling axe and a log splitter if money allowed - you can split logs with an axe but the log splitter is the tool to use. (most axes are to slender to split wood down the grain and it can prove a danger)
Assuming you're not doing carpentry, I would get a bow saw with some length to it with spare blades - they are light, dont bind in the cut and their only restriction is the depth from the frame to the blade, will limit the diameter of what you are cutting.
hand axes are cheap on ebay - the larger ones can get expensive 20 odd quid - the bow saws are not expensive.
Please bear in mind these things are risky if not sharpened - sharpening stones are cheap and you may want a file if you get 2nd hand axes so as to restore the edge - Sharpening saws is a different ball game and a lot of modern blades are designed to be chucked not sharpened.
If your looking to saw a reasonable quantity of wood for fuel then I would recomend a two man saw, which will take sharpening with a file - see my post from yesterday in 'what preps are you doing this weekend' I think.
