I buy no name ram from taobao. It was $22usd per piece back when the cheapest was $30 on amazon. It's has no heatsinks, just exposed pcb and memory chips.

But if you are from USA, I think shipping will eat up most savings unless you buy a huge bulk.
https://s.taobao.com/search?q=ddr4+4gb&type=p&tmhkh5=&spm=0.0.a2227oh.d100&from=sea_1_searchbutton&catId=100