This text comes from The Book of Scottish Song, edited by Alexander Whitelaw, a historical songbook transcribed on Wikisource and reproduced from the pinned revision linked below.
As I cam' doun by yon castle wa',
And in by yon garden green,
O there I spied a bonnie, bonnie lass,—
But the flower borders were us between.
A bonnie, bonnie lassie she was,
As ever mine eyes did see:
O five hundred pounds would I give,
For to have such a pretty bride as thee.
To have such a pretty bride as me,
Young man, ye are surely mista'en;
Though ye were king o' fair Scotland,
I wad disdain to be your queen.
Talk not so very high, bonnie lass,
O talk not so very, very high;
The man it the fair that wad sell,
He maun learn at the man that wad buy.
I trust to climb a far higher tree,
And harry a far richer nest:
Tak' this advice o' me, bonnie lass,
Humility wad set thee best.