The coupon policy at Target doesn’t restrict the use of a coupon on an item made free by a promotion, but keep in mind that your store may refuse to accept it.
Buy 4 Sally Hansen Xtreme Wear Nail Polish $2.49, regular price
Buy Three Get One Free starting 8/4
Use four $1.00/1 – Sally Hansen Nail Color Product, excluding Complete Salon Manicure and Salon Effects Real Nail Polish Strips – (redplum.com)
Or $1.00/1 Sally Hansen Nail Color, excludes Complete Salon Manicure and Salon Effects Real Nail Polish Strips from RP 7/28 (exp 8/28)
Final Price: $0.87 each, when you buy 4USD