Matthias wrote, which made me laugh. The opening chapter(s) of Capital Vol 1 is very odd, and weirdly mundane at the same time. Robert Wolff gives the wittiest commmentary on what he is trying to do in his little book 'Moneybags is so Lucky'. Another excellent commentary is the late Geoff Pilling's Marx's capital. The Cleaver/Althusser approach (which is supported by a letter from Marx to a reader struggling with the early chapters) is wrong, I think, because it reduces the logical method of reconstructing the inner structure of capitalism to an historical account.
But it really is worth it. The secret is that his method (say, philosophical approach) is quite different from ordinary economics, which is derived from empiricism and Newtonian 'laws'. Marx takes all of the categories of the economic science of the day, but he relates them to each other (in a hierarchy) in a similar way to the one that Hegel uses in the Science of Logic to relate the categories of logic. That is, he tries to show that each further development towards greater complexity in the structure of Capital arises out of the limitations of the previous structural form. So in chapter one, he is showing how exchange is a reflection of value in the material form of another commodity; and that the limitations of exchange can only be resolved in the appearance of a special commodity, the money commodity. Whereas in the economics of his day, the different laws of exchange were simply adduced and heaped up, Marx's account is dynamic, showing how each stage is a necessary development forced by the limitations of the preceding. That goes right through to the creation of surplus value, accumulation and what the mainstream economists called the law of diminishing returns. Marx is trying to show that these problems are not incidental, but a necessary component of a social system which recreates its own.
The approaches that try to sidestep the first chapter, which is to say the Hegelian-logical re-working of the categories of economics, end up side-stepping the content of what Marx is telling us, and enjoying what he gives us, essentially, as a by-product, a good historical account of capitalist development.
There are many attempts to short-cut the reading of Marx (here is one that I quixotically made, trying to list Marx's contributions http://lists.econ.utah.edu/pipermail/marxism-thaxis/1997-October/004261.html ), but in the end, the best way is to read Marx, in the order that he expected it to be read, that is, starting at the first page.