best one time purchase apps to buy under $20

hey guys! its my birthday coming up and I am planning to gift myself a new Mac app this time and my budget is $20. I would like that to be a one-time payment app as opposed to a subscription based app. Do you guys have any recommendations?

Here are some apps I already own:

- Better Display
- Klack
- Daisy Disk
- Alfred
- Clop
- PopClip
- Shottr
- Dropover

Thanks!

If they offer a student discount that would be awesome too!

Edit: I forgot to add but I own Swish as well! Amazing app to try for those of you who don’t have it, it’s pretty cheap too! and they offer a 33% student discount!