A small job shouldn’t need this much remembering.
A purchase is easy to remember until you need the date, the amount or proof of purchase. Then the search moves between email, a drawer and your photos.
Here’s the simpler next step.
Upload, email or enter receipts in one place. Review the details that have been read and keep the purchase record where you can return to it.
You do not need to organize your whole life before one tool can help. Start with the thing you keep having to find, remember or reconstruct.