no strings attached
Without conditions or restrictions, as in They give each of the children $10,000 a year with no strings attached. This expression dates from the mid-1900s, although string in the sense of “a limitation” has been used since the late 1800s.
The American Heritage® Idioms Dictionary Copyright © 2002, 2001, 1995 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company.