PaintShop Pro is good but not particularly cheap:
http://www.paintshoppro.com/en/products/paintshop-pro/
For designing leaflets, etc, Serif PagePlus Starter Edition is superb (and free!):
http://www.serif.com/desktop-publishing-software/?mc=FSSPAGEPLUS
Serif used to offer a free version of their (equally good) image editing software on their website. It's now been discontinued but seems to be still available here:
https://photoplus.en.softonic.com/
For a full 'professional' photo editing program (that's as good as the 'full' versions of Adobe Photoshop but doesn't cost a penny), try GIMP:
https://www.gimp.org/
(It's got a very steep learning curve but, if you want the very best from your images, it's worth the effort).