Is $900.00 too cheap for an engagement ring?

Im totally in love! Matt is in the army. He proposed in January before he left for melbourne.
I am so confused as to why he bought me this engagement ring.I told everyone we knew what I liked.
It is nothing that I wanted plus it was cheap.
It cost less than what i make in a fortnight.
I feel that I am cheap and not that important?What was the hurry?.I wasn't pressuring him at all!
I cant stop thinking about it.