Thanks but what do you mean by this "If you do not show prices for guest" - shopper can not register and have not access to our shop unless they have a username and passsword provided from us
If your prices are restricted to the shopper group Standard, Google will not be able to access your prices, because Google visits your site as guest.
If a user logs in, the user will be treated as in the group Standard, only after logging in, the user will see prices.
Please check, where you have restricted the access to the prices.
Once you can do it in your product, but you can also show different prices for different shopper groups. Check the setting in each individual shopper group for that.