Por la compra de 4 unidades iguales o combinadas de los siguientes artículos, GRATIS el de menor importe

{ "offers": [ { "sales_reference": "001020666600885 ", "seller": { "identifier": "001" } }, { "sales_reference": "001020648302345 ", "seller": { "identifier": "001" } }, { "sales_reference": "001020666600349 ", "seller": { "identifier": "001" } }, { "sales_reference": "001020666600356 ", "seller": { "identifier": "001" } }, { "sales_reference": "001020666600877 ", "seller": { "identifier": "001" } }, { "sales_reference": "001020666600430 ", "seller": { "identifier": "001" } } ], "subsite": { "identifier": "supermarketExpressStore", "parent": { "identifier": "supermarket" } }, "query_params": { "centers": { "home_delivery": "0006" }, "is_full_documentation": false, "is_include_offer_availability": true }, "query_list_get_method": "001020666600885___,001020648302345___,001020666600349___,001020666600356___,001020666600877___,001020666600430___", "delivery_get_method": { "delivery_type": "home_delivery", "center_id": "0006" } }