Target has the distasteful feature that in-store prices differ from online prices. So if you go and browse you pay more than you would by ordering online and driving to the same store and picking it up. Maybe you could argue for the online price?
Are you sure you have the right store selected? I like to get the aisle numbers and see if something is even in stock on the website before I go and I've never had a price mismatch.
Walmart's pricing is also accurate but their stock indicator isn't as good as target's.
Supplements are a scam industry, so you’re always going to have issues there, that’s a feature of the business.