The "buy in bulk" advice is not always good advice and for a long time it was actually making my situation worse
I want to push back a little on something that gets repeated constantly in frugal and personal finance spaces because I followed it for a while and it backfired on me in ways that took me too long to recognize.
The standard advice is that buying in bulk saves money per unit and therefore you should always buy the larger size or the warehouse quantity when you can. And mathematically that is often true. But there are a few things that advice assumes that weren't true for my situation. It assumes you have the storage space. It assumes you will actually use all of it before it expires or goes stale. And most importantly it assumes you have enough cash on hand that spending $40 on a bulk item instead of $8 on a regular size doesn't create a problem elsewhere in your budget that week.
For about a year I was regularly buying bulk quantities of things because I had convinced myself it was the smart financial move. What was actually happening was that I was spending more money upfront than I had, occasionally letting things go to waste because I couldn't use them fast enough, and creating these weird gaps in my weekly budget because I had front loaded my spending on bulk items. I was optimizing for cost per unit while ignoring cash flow, and cash flow is what actually determines whether you can make it to the next paycheck.
What works better for me now is buying the regular size of most things and only going bulk on the three or four non perishable items I use constantly and know I will finish. Rice, oats, coffee, dish soap. Everything else I buy as needed. My weekly spending got more predictable and I stopped having those weeks where I was technically "saving money" but somehow couldn't aford anything