GREP is not necessary here.

Assuming the paragraph style applied is using the roman/book font, and you’re using a bold character style to apply the bold style to the SKU (via a Nested style as you said), then just add a couple more nested character styles to that “price” style.

Like this:
1. Bold up to 1 tab [what you’re doing already]
2. None up to $ [Enter that character in the right-most field]
3. Bold up to 1 soft return [choose Forced Line Break from the right-most dropdown]

You don’t need to have one for hard returns, because nested styles always end at the end of a paragraph. That is, if it can’t find a soft return, it’ll just apply to the remaining part of the paragraph until the hard return.

AM

If you turn off Smart Text Reflow, and then delete the extra blank page (or just the empty threaded text frame on it), do you get an overset in the previous frame?

If so, open Story Editor to see if there is a red line indicating the overset text. It’s possible that it’s an empty paragraph, or even an end-of-story inline graphic that got lost somewhere. Click after the last visible character that ends your story, and press Command-Shift-End (windows: Control-Shift-End) to select all the phantom text after your cursor, and then press Delete/Backspace to delete the selection. See if that works.