'a proof of purchase' is a correct and usable part of a sentence in written English.
You can use it when referring to a document which serves as evidence that you have purchased something. For example: "Please send me a copy of the proof of purchase for the new laptop I purchased last week."
To get most rebates, the bar code from the product's package must be mailed in with a proof of purchase within a certain time.
He promised to distribute some of the remaining $39,567.68 by sending $5 checks to the first 200 readers who mailed in a proof of purchase.
To get the cash back, customers must fill out information on the older devices they are trading in at Motorola's "Switch" Web site and provide a proof of purchase for one of the Motorola devices.
Webber outlines further problems with how subsidy schemes work: "The funding body wants a proof of purchase and the publisher is unable or unwilling to buy the book unless there is a guarantee for the funding.
Finding and filling out a claim form, mailing or faxing it with a proof of purchase and then waiting for money to arrive can take nearly two months, he says.
All songs without a proof of purchase would be assumed to be unauthorized and not accepted into the system.
(You need to fill out a counterfeit report, provide a proof-of-purchase statement or receipt and send your bootlegged Windows discs back to Microsoft).
Once you buy something, the app lets you post that news easily to your Twitter or Facebook feed, or e-mail it to others, and it stores a proof-of-purchase voucher page that you show to a cashier.
And, as a special thank-you to those who've already bought those products, the first forty-seven thousand five hundred of you who send us a proof-of-purchase seal will receive a legal-liability release suitable for signing and sending right back to us.
By Dec. 31, 1999, I had a collection of 110 proofs-of-purchase from 55 lunches of Colonial Chicken Pie and 55 dinners of Chicken and Vegetables Marsala.
