bhphotovideo[.]com/c/product/1505339-REG/corel_psp2020ulefmbam_paintshop_pro_2020_ultimate.html
I *think* the recent Humble Bundle was the lowest price ever, but this is the lowest I've seen for PSP only, & a decent deal considering I usually only see it below $50 once or twice a year, and some years not at all.
It has some stuff that Photoshop & The GIMP etc. do not, and is pretty comparable to Photoshop with the notable exceptions that it doesn't come close to Photoshop working with RAW images, and it doesn't have Photoshop's AI for selections. Then again at this price you could buy Corel's Aftershot when it's on sale to better work with RAW files [it's Corel's answer to Lightroom], and still spend less than 1/2 the cost of a year's subscription to Photoshop & Lightroom.