Generally, physical stores with a little doorway will not sell fakes, but it is hard to say how cost-effective it is.

If you want to buy, you must ask for a standardized test certificate, which can be rechecked in official website, a testing institution.

The Jade Guanyin you mentioned has some gold on it. I don't know if it's the kind of Guanyin with thousands of gold inlaid on its surface. That product is called "jade inlaid with gold". Please do your own Baidu search.

Just look at other people's questions and answers.

Generally, the market value of such products is within three figures.

I hope to have some reference.

Good luck!