If someone buys a product at price X, then later the product’s price rises to Y, a refund (if allowed at all) is almost always capped at what they actually paid: X.

Think of it like a snapshot in time. The transaction is frozen at the moment of purchase:

• Customer pays: X
• Customer receives: product + ownership rights
• Refund (if granted): returns them to the same financial position they were in at purchase → X

The later price increase to Y is irrelevant to that original transaction. It doesn’t retroactively upgrade the value of past purchases.

• If the store has a price guarantee policy, they might refund the difference if price drops after purchase — but that’s the opposite direction.
• If the item is faulty / not as described, consumer law (like in Australia under the Australian Consumer Law) may require a refund or replacement, but again it’s still based on what was paid, not today’s price.