Alas, while all kinds of payment system changes were occurring between 1870-1930 in the United States (the scope of this study), Zelizer ignored them all. Her focus is largely on domestic monies: how husbands controlled the family money, how social replacements for husbands (relief agencies -- not her formulation) did the same, with some sidelights on gifts, tipping, and payment for ambiguous social services (taxi dancers and charity girls).
You'll hear no argument from me on the basic thesis (it is wrong too think money somehow operates outside of all the personal/social forces, acting as a leveling/greying/rationalizing agent). Nor do I have any problems with where she choice to zoom in. I am a little sad that she missed opportunities to explore how forces in the larger world may have influenced relief agencies (domestic arrangements, gift practices, etc.) -- they only finally break through in the discussion when it reaches the 1930s.
What I will say is that a close look at payment systems might have been a more compelling way to argue the thesis. But I don't think the basic thesis is the real thesis. Zelizer seems to hover at the intersection of a white/male centric view of the world (the "normal" consumer is person with a paycheck and without dependents, typically not a dependent) and a desire to validate the perspective of, well, everyone else: the people who don't have paychecks, the people with dependents, the people who are dependents, etc. Those not-"normal" consumers are the natural prey of people who think they know better how to spend the money that is so hard for them to acquire, and Zelizer does a bang-up job of describing out how didn't just fight back. They reframed successfully. But Zelizer doesn't seem to really get framing, which is hardly surprising, given the time frame this was written. (Har de har har there for the inadvertent pun.)
Not a waste of time, but I won't keep my copy. I will hopefully eventually read the other Zelizer book I have lying around, _Pricing the Priceless Child_.