Desigual currently has an up to 50% off sale across the site, which is the main saving you will see right now. That site wide sale is best if the items you want are included in the reductions, while the other active offers give fixed price options or delivery savings for certain purchase sizes.
For big baskets where many items are reduced: The up to 50% off everything is likely the biggest saver when several of your chosen items are in the sale. For example, on a $120 order made up of sale items reduced by 50%, you pay $60 after the percent discount, so you save $60 (original $120, percent 50% off, final $60, saving $60). Use the site sale pricing at checkout since no code is required.
For orders of $80 or more where you want free shipping: If your cart reaches $80, free shipping applies, so factor that into the total. If you have full price items not in the sale, free shipping can beat small sale discounts on a single item because it removes delivery fees. Compare the sum of item prices with 50% off applied where relevant plus the saved shipping cost. The free shipping threshold is $80, so when your pre delivery total is $80 or higher the shipping charge is removed.
If you are buying the multi position backpack: That product is sold at a marked price of $159. If that is the single item in your cart, the fixed price is the offer to use because the price is as marked; you cannot combine it with the site sale unless the product page shows it reduced. The backpack price example is $159 (fixed price 159, final $159, saving depends on any previous full price but none given here).
If you want a gift card or a specific small item: Gift cards start from $20, which is a clear fixed entry price. Note gift cards cannot be used in conjunction with any other offers. The Leather Heart Belt shows 30% off as an item level reduction; that applies only to that belt and is already reflected in the pricing on the product page, and it is from the women range so check item eligibility before relying on it.
When choosing between these offers, total up the final price for the same basket under each applicable option and pick the lower total. The site sale and the item level marked prices are mutually exclusive only when a product is already marked; gift cards state they cannot be combined with other offers. Start by adding your items to cart, note the sale price shown on each product page and whether that product is marked at a fixed price, then take whichever option leaves you paying the least.