How do I find a code that actually works?
Start at the store's own coupon page, which is the only listing guaranteed to be current, then check whether a code beats the sale price already showing. Codes with a stated expiry are worth more than codes with none.
It says invalid. What did I do wrong?
Almost always a condition you did not meet: a minimum spend, an excluded brand, or new customers only. The promo box usually says which. If the conditions all check out, the offer has ended.
There's no code to copy. Is that right?
Both exist. Some offers need a string pasted at checkout; others attach the discount to the link and apply it once the store page loads, reverting to full price if you arrive another way.
Can I use two codes at once?
Usually not. Most checkouts accept one promo code per order, though a code will often combine with a sale price, free shipping, or a rewards discount.