However, it really IS helpful to make a larger purchase. You can think of convenience-purchase-pricing of things you use regularly at home like loan-sharking at exorbitant rates. It hits those least capable of affording it.

The flip side is you get a huge benefit from scrounging for the money/time to get the bulk package. It's like an small investment that returns 200%.

My wife makes fun of me, but I often buy a large amount/quantity of a few items at the grocery store, i.e. ones that we already use regularly, that I know the usual price of, so I know when a "sale price" (or bulk price) is actually a good deal. This only really works well for things that are shelf-stable, of course.

Diapers are definitely one of the things you should try to buy in large packages when the prices are low. It genuinely is hard for a single mother to do this, but there's a significant payback in both money AND time.