Don’t know what got me thinking of this book, but after some online searching for the title, which I’d forgotten, I found a copy of Beware of This Shop by Carol Beach York. The time period isn’t explicitly stated, but my guess is that it’s meant to be late nineteenth-century/early twentieth. A young woman buys a china shepherdess from a newly-opened and somewhat mysterious shop. She gradually learns that the store’s objects have strange and unpleasant effects on their purchasers. She’s pressured to take a job as a sales clerk there and becomes even more enmeshed in the strange goings-on of the store. It’s a slim book and the ending isn’t cut and dried.
I’ve done a little searching, but I can’t find all that much on the Web about the author or this book. I did find this thread so it’s good to know I’m not the only one who felt similarly.