Albert Barnes Commentary 1 Samuel 18:23

"And Saul`s servants spake those words in the ears of David. And David said, Seemeth it to you a light thing to be the king`s son-in-law, seeing that I am a poor man, and lightly esteemed?" — 1 Samuel 18:23 (ASV)

A poor man and lightly esteemed — Compare to Psalm 119:141. He was poor and therefore unable to pay a sufficient dowry (see 1 Samuel 18:25).