Historical clue formulations

• There's often a lot of them for sale — 2021-01-15
• They're old and tired — 2017-05-13
• What a lot may have a lot of — 2007-03-03
• They've been on the road many times — 2007-01-26
• There are lots of these for sale — 2005-06-12
• Items sold in lots — 2000-03-04