In just four lines, the speaker sets two images side by side: eating snow and counting ways to make money. Snow is cold, empty, and free, the kind of thing you eat when you have nothing else. Money is the opposite, something the speaker is anxiously working out how to get. Put together, they suggest someone who is hungry or short of cash and whose mind has narrowed to survival.
The second stanza turns this into a kind of confession. "Giving myself wholly up to matter" plays on the title. "Materialist" can mean someone who loves money and things, but it can also mean someone who believes only the physical world is real. The speaker seems to slide between both ideas. There's a note of surrender, maybe even a strange relief, in letting go of higher concerns and accepting the body, its needs, and the pressure of money.
The mood is stark, cold, and quietly wry. Nothing is dressed up, and the plain tone makes the bleakness hit harder.