Can I get a refund on a sale?

Not to put anyone down but what the question sounds like to me is that he bought a game and a week later it went on sale and I am assuming that he possibly wants a refund either for the difference or possibly a refund for the full price that he paid for
it and then wants to buy it again at the sale price.

Either way to the original poster you would have to go through the refund request process like some of the other people have posted and there is no guarantee that it will be approved.

In my experience you cannot get a refund for a game you bought on sale.

How to request a refund

1. Sign in to the Xbox Refund Request Solution with your Microsoft account. Be sure to sign in from the account used to make the purchase. If you have multiple accounts, you can check
   the purchase history on each to find the charge and order number.
   Note If you don't know your Microsoft account email address or password, use the Lost Account Solution or
   the Lost Password Solution.
   
2. You will be prompted to verify that you are signed in to the correct account and have the order number(s) for this purchase.
3. You will then be provided with descriptions of the different types of reasons for requesting a refund, and what additional information is needed to process a refund request. Select the reason you are requesting the refund and review this information carefully.
4. You will either be directed to the appropriate self-serve resource, or provided with a link to the refund request form to fill out.

Note If you don’t have an Xbox account, please request a call from Xbox Support so we can remove your payment instrument to prevent any further charges. You will need to contact your financial institution for a refund.

How to complete the refund request form

1. Enter the name of the product for which you’d like a refund.
2. Your name and the email address associated with your account will be auto-filled after you sign in. If you have a preferred contact email address, it can be updated on the form.
   Note This will not change the email address you use for sign-in.
   
3. From the dropdown menu, select your reason for requesting a refund. Be sure to choose the same reason you selected in the Xbox Refund Request Solution.
4. Provide additional information as required.
5. Provide the date of purchase and order number. If you have multiple requests on this account, list all order numbers and dates separated by a comma. To find the order number, you can check
   the purchase history.
6. If there is additional information you would like to provide, use the open text box.

After you submit your refund request

You’ll receive a confirmation email and should get a response from the support team within 72 hours.

• To cancel your refund request: Reply to the confirmation email requesting cancellation.
• If you don’t hear back from the support team within 72 hours: Reply to the confirmation email requesting an update on the status of your request.
• To track the status of your refund request: Check your Order history.
• If you have a question once your request is processed, reply to the decision email.
  
  Note We will respond if we have additional information to provide.
  

You can't get a refund for a game that was on sale. The refund page is available only for digital games purchased at full price.

I know they do cancellations/refunds for pre-orders if you contact support, but I don't think they refund digital purchases. Like stated already.