Showing you an easily sortable list of which apps you've purchased is one of the things the Play Store does not do. You can see a list of all the apps you've ever installed, but you can only sort that by date installed or alphabetically. Thankfully,
a new an app is available to help solve this problem (Edit: it's not new, but it is great).
Purchased Apps, from developer Asapha Halifa, gives you the same list but with much more powerful display options. Sort by price (high to low) and you can easily view all of the apps you've spent money on, and tapping on them takes you straight to the Play Store so you can install them again. This is especially useful for games you've forgotten about despite spending a few dollars on.
The app is pretty basic in design and uses dated looking Material Design stylings, but it gets the job done. In the slide-out menu, there's a total showing you how much you've spent on apps and games altogether, plus there are categories so you can look at particular types of apps. There are also options to change currency and date format if you need to.
All in all, it's a really neat app that serves its purpose well. You can even export and share your list with others. It does show ads, but they're not too intrusive. Unless you're like Rita and you keep every Play Store receipt email you've ever received for easy sorting and searching (yeah, me neither), this app could be really useful.
One thing that's unclear is whether apps you've installed during a sale show up at the sale price or their current full price, but I've reached out to the dev to find out (Edit: It does show the price you actually paid). Give it a try by installing it via the Play Store or downloading it from APK Mirror.