Hi,
I have corrected some of them successfully. AliExpress products are harder to fix, and they seem to have another price discrepancy problem that makes prices change spontaneously after they have been saved properly. I have had to delete those products.
Re: the 19.99 problem, Make sure the supplier says there is inventory available and that the quantity is correct when you are saving all the information for your product. Like on the screenshot I attached. Look at the “track quantity” and “continue selling when out of stock” sections and make sure they are right. I have found that saving and saving, then previewing, and if it still says 19.99 etc., try reloading the page a couple of times and check again. Make it active and check again. So far this works.
good luck!
Hazel