Melba Montgomery had already recorded a series of duets hits with country music artists George Jones, Charlie Louvin, and Gene Pitney during the 1960s (the most successful of those being "We Must Have Been Out of Our Minds" with Jones). In the early 1970s, she began focusing on a solo career, but did not have notable success.

Eventually, she began recording for Elektra Records, where her struggles continued. Then, Howard forwarded a song to Montgomery he thought would be perfect for her: "No Charge." She recorded "No Charge" in early 1974, and it was released that April. By the end of May, Montgomery enjoyed her first taste of solo success, reaching No. 1 on the Billboard's Hot Country Singles chart. The song also reached No. 39 on the Billboard Hot 100.

Commenting on the record to Tom Roland in The Billboard Book of Number One Country Hits, Harlan Howard said, "I've never written a song that moves people so much. I've had guys tell me they almost wrecked their truck when they heard it 'cause it made them cry. I had a lot of delightful records in many different languages on that song, but I guess that's probably my favorite song as far as impact is concerned."

A young boy hands his mother an itemized list of charges he says he's owed for performing various chores and comes to collect; the singer performs this in spoken word. The mother responds (singing) by reminding her son about all the things she's done for him, that she never asked him to pay for services rendered and that, all things considered, "the cost of real love is no charge."

Enlightened, the young boy realizes that his mother is right and changes the amount due to "paid in full" (once again, narrated) before the singer sings the moral. "No Charge" was one of the few songs that talked about motherhood during this time, which might be one of the reasons why it was so popular.

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Wikipedia