This Type 4, Memorial Reverse (Zinc) 1991 D Lincoln Cent, MS69Red is 1 of only 4 to have been graded MS69Red. One was sold by BM June 2010 for $5,405 and PCGS identifies a valuation of $3,500
NGC doesn't show any 1991 Lincoln Cent in MS67Red on their population but do show a $2,000 value on their price guide and apparently now require an item be shipped before verification can be done online? Thats new, I think.
This coin is great for someone wanting a top pop to complete the collection. Based on data availability this is a $2,000 - $5,405 Lincoln Cent. On this website I can afford to discount the coin because I am not paying 13.8% - 20+% platform fees