Really good question. Pricing hand knit items is tough. I take into consideration time it took to knit, cost of materials, and I research pricing of similar items.
Secondly, I am influenced by how much I want to make another one. For example, I love knitting Christmas stockings so I am willing to let them go at a certain price. I like knitting plush animals, but sewing together is a bit tedious, I price them accordingly.
Your pillow, the pics show quality knitting tension, hence quality work. You are including stuffing. I don't want to tell you what to price it at, but research similar items and check out the plush animals. Your pillow is similar, with fewer seams, but a knit in design on the front. All things to consider.
Good luck.