Blendle tried this, but it didn't really work out for them.
My point really is that I'm willing to pay a reasonable price, but I'm not willing to sign up in perpetuity and I'm not willing to go through an onerous cancellation process. Treat me like a valued customer and let me buy the pieces I want. I don't really care to support parts of the paper/news I don't consume - which is what a subscription does.