Student or Learner
In Academy Street by M. Costello, the narrator's son died.
"The grief was so deep her eyes could not weep. All good had gone out of the world. And to think that the world still went on. She saw again children playing, people eating and drinking and laughing, the purchase of life. Birds, books, the notes of a cello, the glossy green heads of ducks in a pond, all indifferent"
May I read 'the purchase of life' as 'life with buying and selling activities'?
No, your interpretation is not correct.
The phrase feels familiar to me, though I can't quite put my finger on it.
The key here is the word "purchase". It is not about buying or selling, but rather speaks to one's "grasp" on a thing. So it is talking about our "hold on life".
Or perhaps, "Life's persistence", the hold that Life has on the world, since she is experiencing a dichotomy between her unrealistic feeling that life should stop everywhere (because she feels life has stopped for her, perhaps?) versus the obvious fact that it continues as usual.