For those of you who do not like the subscription model of Adobe Photoshop, but would like to have some additional process options than are available in GIMP, Serif's Affinity Photo image editor is now on sale for 50% off for only $27 US. This is a one-time fee, no subscription, and so far Serif has not charged for updates in the several years I've had my copy. This is a good deal for a capable image editor that also has built-in astrophotography tools like stacking and gradient removal, and can work directly in 32-bit, which Photoshop surprisingly can't. Although I primarily work in Photoshop because it's an app I've worked professionally with for over 30 years, this app has come in handy for me when PS drops the ball.
Serif has a triple suite of graphics apps akin to Photoshop, Illustrator, and InDesign, so if you should have a (non-astro) need for such tools, they are all on sale for 50% off, and they all come with trials if you're interested.