I found this story whilst correcting digital text in a Newspaper published in New South Wales, Australia;
The Kiama Independent, and Shoalhaven Advertiser.
This particular article published on Thursday 3 August 1865 Under the title MISCELLANEOUS.
I have not come across the story in any other local publication.
It's probably in publications in the United States, but, just in case it isn't, and rather than see it lost, I have repeated it here, for your interest.
Oh yes, and knowing little about the life and times of Lincoln, and knowing how aussies like to tell a bit of a yarn, I cannot guarantee the authenticity of the story.
The 'William D. Kelly' I would assume to be William Darrah KELLEY 1814-1890.
'Seward' would be Lincoln's Secretary of State, William Henry SEWARD 1801-1872.

Philadelphia, on the 24th April, the Hon.
William D. Kelly, who was on terms of
intimacy with the late President Lincoln from
the day of his election to that of his tragical
death, delivered an address upon his life and
character before the Girls' High and Normal
School, in the course of which he related the
following anecdote:—One evening in the
executive chamber there were present a num-
ber of gentlemen, among them Mr. Seward.
A point in the conversation suggesting the
thought. Mr. Lincoln said, " Seward, you never
heard, did you, how I earned my first dollar."
" No," said Mr. Seward. "Well," replied he,
"I was about eighteen years of age. I be
longed, you know, to what they call down.
South, the 'scrubs,'— people who do not own
land, and slaves are nobody there. But we
had succeeded in raising chiefly by my labor
sufficient produce, as I thought, to justify me
in taking it down the river to sell. After
much persuasion I got the consent of my
mother to go, and constructed a little flat boat
large enough to take the barrel or two of
things that we had gathered, with myself and
little bundle down to New Orleans. A steamer
was coming down the river. We have, you
know, no wharves on the Western streams,
and the custom was, if passengers were at any
of the landings, for them to go out in a boat,
the steamer stopping and taking them on
board. I was contemplating my new flat boat,
and wondering whether 1 could make it
stronger or imporve it in any particular, when
two men came down to the shore in carriages
with trunks, and looking at the different boats,
singled out mine, and asked, "Who owns
this ?" I answered somewhat modestly, ' I do.'
"Will you," said one of them, "take us and our
trunks to the steamer?" "Certainly," said I.
I was very glad to have the chance of earning
something. I supposed that each would give
me two or three bits. The trunks were put
on my flat boat, the passengers seated them
selves on the trunks, and I sculled them out
to the steamboat. They got on board, and I
lifted in their heavy trunks, and put them on
deck. The steamer was about to put on steam
again; when I called out that they had for
gotten to pay me. Each of them took from
his pocket a silver half-dollar, and threw it on
the floor of my boat. I could scarcely believe
my eyes as I picked up the money. Gentle
men, you may think it a very little thing, and
in these days it seems to me like a trifle; but
it was a most important incident in my life.
I could scarcely credit that I, a poor boy, had
earned a.dollar in less than a day—that by
honest work I had earned a dollar. The world
seemed wider and fairer before me. I was a
more hopeful and confident being from that
time".

More Lincoln reading from Australian Newspapers