One of the simplest tricks you can use to change the look and feel of a room is to change the pillows and pillowcases in the room. Just by changing their color themes can change the whole room.
If your sofa or your chairs are in one color, no patterns, and colors are neutral, it is even easier to create a combination that works well. Keeping the pillows in approximately the same colors but different patterns makes the combinations calm and interesting at the same time.
Pillowcases and pillows come in various materials, patterns and styles. They also come in various price classes. The pillow above from Svensk Tenn and costs SEK 950. I think that is a ridiculous price for a simple pillow. This is printed on linen. I would never pay SEK 950 for a pillow, no matter it being a famous pattern like this one, or that it covers a down-pillow (just guessing that it does).
Some pillowcases are made by famous designers, like the above by Nadja Wedin. Costs SEK 695. I think that is ridiculously expensive as well.
This one is from, MIO and costs SEK 359. Still too expensive in my opinion.
It is EASY to make a pillowcase all by yourself. The pillows inside can be of any kind and you can find inexpensive ones at IKEA for next to no money. IKEA also has pillow cases for reasonable prices.
All you need to make the simplest pillow case is cloth of the size of the pillow it should cover + some extra for the sewing. If you make a pillowcase in envelope-style, some more cloth than the actual pillow. You can close the pillow case either with a zipper, or buttons, or straps. If envelope style, the cloth itself closes it.
For some time now pillows covered by knitted or crocheted covers have been seen in various interior design magazines and pictures. The above is about the simples model there can be to knit yourself. Why pay a lot of money to buy one? Unless, of course you have no knowledge of how to knit… You only need yarn of some sort (preferably thick yarn) and 2 knitting needles. How you close the cover is up to you.
If you Google the internet for knitted pillowcases you will find plenty of descriptions about how to make them.
If course you use colors according to your own wish, and patterns too, just as if you were knitting a sweater…
Or crochet the pillow case. Use your imagination. Pillow cases do not need to be expensively bought.