Affinity Photo is very similar to Adobe Photoshop (and is compatible with Photoshop files) but can be bought for a reasonable one-off price and does not have a subscription model. This software will let you create artwork or edit existing images to make 2D elements or skins for backgrounds, sprites, and more.

Affinity Photo might seem intimidating with its many options and tools, but there are lots of good video tutorials on their website and once you’ve got the hang of the software the sky’s the limit.