The song you're looking for is a country ditty by Jimmy Dean from 1976 called I.O.U. https://www.youtube.com/watch?v=TXvwgNVhz88
Many people look through their wallet or their pocketbooks
And way down at the bottom, past the credit cards and baby pictures and so on
You usually find a little 'ol piece of dog-eared poetry.
I was cleaning out my wallet the other day and ran across a whole bunch of I.O.U's
Some of 'em 35 years overdue.
And you know the funny thing, all these I.O.U's are owed to one person
And I kinda felt like that maybe now would be a pretty good time for an accountin'.
Mom, I sure hope you're listenin'.
Sweet lady, I.O.U. for so many things ...
A lot of services, like night watchman, for instance...
Lyin' awake nights, listenin' for coughs and cries and creakin' floorboards
Hah-hah, and me comin' in too late.
Boy, you had the eye of an eagle and the roar of a lion
But you always had a heart as big as a house.
I.O.U. for services like, uh, short-order cook, chef, baker...
For makin' sirloin out o' hamburger an' turkey out o' tuna fish,
And big ol' strappin' boys out of leftovers.
I.O.U. for cleanin' services,
The daily scrubbing of face and ears, all work done by hand.
And for the frequent dustin' of a small boy's pants
To try to make sure that you led a spotless life.
And for washin' and ironin' that no laundry could ever do.
For dryin' the tears of childhood and ironin' out the problems of growin' up.
I.O.U. for services as a bodyguard,
For protectin' me from the terrors of thunderstorms and nightmares
Hah, And too many green apples.
And Lord knows, I.O.U. for medical attention,
For nursing me through measles, mumps, bruises, bumps, splinters, and spring fever.
Oh-oh, let's not forget medical advice, important things like,
"If you keep on scratching that, it'll never get well,"
Or, "If you cross your eyes, they're gonna stick like that".
And probably the most important advice of all,
"Boy, you be sure you got on clean underwear, in case you're in an accident".
And I.O.U. for veterinarian services,
For feeding every lost dog that I dragged home at the end of the rope,
And for healing the pains of puppy love.
And I.O.U. for entertainment
Entertainment that kept the household goin' through some pretty rough times
And for wonderful productions at Christmas, the Fourth of July, Birthdays
And for making make-believe come true
And you did it all on such a limited budget.
I.O.U. for construction work, for building kites and confidence, hopes and dreams an'
Somehow you made them all touch the sky
And for cementin' together a family
So it would stand the worst kind of shocks and blows
And for layin' down a good strong foundation to build a life on.
I.O.U. for carrier charges
For carryin' me on your books for the necessities of life
That a growin' boy somehow, well, they just gotta have.
Things like, hah-hah, a pair of high top boots
With a little pocket on the side for a jack-knife.
And one thing, Mom, I'll never forget
When there were two pieces of pie and three hungry people
You were always the one who decided, well, I'm not really that hungry anyhow.
These are just a few of the things for which payment is long overdue
The person that I owe 'em to worked very, very cheap
She managed by simply doin' without a whole lot o' things that she needed herself
My I.O.U's add up to more than I could ever hope to repay
But you know the nicest thing about it all
That I know, that she had marked the entire bill "Paid In Full"
For just one kiss and four little words, "Mom, I Love You!"