Backstory: I'm so tired of receipts, they're wasteful and I lose them most of the time. Most companies still force you to bring in your receipts to return items. While returning an item at a big box store this past weekend, Julia pitched the idea of an app that has receipts for all items purchased.
The Idea: Similar to mint where all purchases are aggregated but generate an actual receipt to return items.
Deep Dive: This would have to integrate with the back end of most major stores and generate a true printable/scannable receipt for purchase at every store. This would help with returns, accounting and gifting. This would help tremendously when filling out expense reports at work, all your purchases would automatically be aggregated for emailing to the accounting department. This is probably the most lofty idea yet but it would save a lot of headache, paper and confusion about who purchased an item. You could do this on blockchain, ensuring all receipts are unique and raise millions with an ICO. I'm half kidding, I don't know enough about crypto to comment but guaranteeing the receipt is yours and unique may be useful.
Validation: Saving trees and creating a standard for receipts would be huge for consumers.
Monetization: If you're able to provide enough value for consumers and remove the burden from stores to track receipts you could charge a licensing fee to B&M stores.