Possible Clues:

• Cost increaser
• Word on two "Monopoly" squares
• See 1-Down, and word that can precede both parts of the answers to starred clues
• State levy
• With 6-Down, one in fear of an audit
• Government's bite
• It's based on purchase price
• Store charge, often
• Word that may follow either word in 17-, 20-, 37-, 53-, and 58-Across
• Strain; levy