I'm in the middle of a refresh of my library, music, front room. The wallpaper under the chair rail moulding has been removed, the walls holes filled and sanded and all cleaned with the ammonia/vinegar/baking soda solution by my wife.
We have generally used the local Sherwin-Williams store near my house for most paint and have an "account" with them. When my wife purchased the near-best wall paint it was $70/gal
And that was after our discount.
Although I'm sure there are less expensive paints available we have always been satisfied with the SW product.
Like many things these days that you don't purchase regularly, prices have increased substantially.