A_540 - Large stores that sell bulky products may use one or more of the following alternative methods to help customers indicate which products they want to purchase:

• Labels with alphanumeric codes on the products and notebook for writing (it is important that the alphanumeric codes have a “control” part to avoid errors in the transcription, e.g. even just one terminal letter. Furthermore, for alphanumeric codes it is it is always better to completely avoid all ambiguous characters, such as zero and the letter “O” for example, in order to further reduce potential transcription errors...) (like Ikea)
• QR code present on the product (even on a label) and “cart” app to use
• Colored labels to stick on products with progressive alphanumeric codes on them (to identify the customer, but actually requires a store employer to check all the labels periodically and payment to be done by the store in a later stage, and it's also a bit unsure)
• Colored NFC present on the displayed product and “cart” app to use (but only if the phone supports NFC)
• Labels to be removed with alphanumeric codes present in special sheets associated with each product and to be stuck on a “shopping” sheet which is then managed at the checkout. The label sheets on the products must be replaced with full sheets by the shop assistants when the labels that can be removed are almost exhausted. If it is established that the labels are to be removed in a certain order (e.g. from right to left, from top to bottom), if the last and penultimate labels have “special” codes the shop can also know when certain label sheets are to be replaced with full ones and do so precisely.