I sell underwear in my store. Underwear usually is sold in bundles (i.e. 3/$33) but you can only have one automatic discount in Shopify, unless you pay for an app.
I've tried almost every free trial app out there, and most are not great customer/user experiences when I tested. I tried the Automatic Discounts app per a Shopify Staff response to a similar thread last year, but this is $14.99/mo. And the discount doesn't show up in the cart.... unless you buy another app for $7.99/mo.
I was also willing to pay a developer at TaskHusky a one time fee, because monthly will add up, but they said this is not possible, at all.