Here's a little search tip to help identify all the receipts and order details for products and services in your GMail account. Simply enter the following and hit search:
subject:(order OR booking OR receipt OR cancellation) -unsubscribe
You can take this one step further by creating a Filter / Rule which will automatically label the emails to give you a visible indication in your inbox. Simply click on the down arrow visible inside the search bar, on the right and you will see the first screen. Click "Create filter with this search", and then you can select the label to apply on the next screen.
Of course, there are more advanced options available in the filter, so you could have them automatically filed, marked as important and (crucially) ensure they are never sent to spam. Above, I have created a very small label using an exclamation mark, which I then set to display in bright yellow - as shown below:
You'll notice that I also have labels "@Waiting For" and "@Followup", which I use to keep track of orders that I am still waiting to receive (as well as to flag email conversations where I am waiting for a reply, or need to follow up on).
If you have any suggestions on improving the search query, please post them in the comments below.
Disclaimer: The search above isn't 100% accurate, and could miss some emails or highlight some spam, but in my experience it does catch aroung 99% of all my order details.