Every BOGO app demo looks the same. The differences that matter appear at checkout, when two offers
Nearly every BOGO app covers buy X get Y, free gift, volume tiers and bundles — feature lists are close to useless for choosing between them.
The real differentiator is the discount engine: apps built on Shopify Functions behave predictably at checkout, older approaches based on cart rewrites do not.
Storefront communication is the second differentiator, because an offer nobody notices converts like no offer at all.
Bundled suites cost less than several single-purpose apps but add weight you pay for on every page load.
Shopify's native discounts handle a genuine buy X get Y, so simple cases need no app at all.
The full guide has the formats, the deadlines and the worked examples.