According to the sources provided, there is evidence that Lipitor's price has decreased significantly in recent years.

DrugPatentWatch [1] shows that the patent for Lipitor expired in November 2011, which opened the door for generic versions of the drug to enter the market. The introduction of generic competition typically results in lower prices for consumers. In fact, a study published in the Journal of Managed Care & Specialty Pharmacy [2] found that the introduction of generic atorvastatin (the generic name for Lipitor) was associated with a significant reduction in the cost of lipid-lowering therapy.

Furthermore, Reuters [3] reports that Lipitor's manufacturer, Pfizer, has faced challenges in maintaining the drug's sales in recent years due to increased competition from generic versions and the development of newer cholesterol-lowering drugs. In response, Pfizer has reportedly lowered the price of Lipitor in an effort to maintain market share.

Overall, while there is no specific data on the extent of Lipitor's price decrease, the expiration of its patent and increased competition from generics have likely contributed to lower prices for consumers.

Sources:
[1] https://www.drugpatentwatch.com/p/tradename/LIPITOR
[2] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6915405/
[3] https://www.reuters.com/article/global-precious/precious-palladium-heads-for-its-best-day-since-1997-on-s-africa-lockdown-idUSL4N2BI4C4