Acts 5

Luke tells us that -

"...a certain man named Ananias, with Sapphira his wife, sold a possession,
2 And kept back part of the price, his wife also being privy to it, and brought a certain part, and laid it at the apostles' feet."  (New Testament | Acts 5:1 - 2)

As many began to live the law of consecration, these two individuals professed that they too were living this law and donated all that was received with the sale of the possession. But Peter, knowing that this was not true confronted Ananias asking -

"...why hath Satan filled thine heart to lie to the Holy Ghost, and to keep back part of the price of the land?
4 Whiles it remained, was it not thine own? and after it was sold, was it not in thine own power? why hast thou conceived this thing in thine heart? thou hast not lied unto men, but unto God."  (New Testament | Acts 5:3 - 4)

The consequence for this representation seems rather steep as -

"...Ananias hearing these words fell down, and gave up the ghost..."  (New Testament | Acts 5:5)

But no only Ananias gave up ghost but -

"...when his wife, not knowing what was done, came in.
8 And Peter answered unto her, Tell me whether ye sold the land for so much? And she said, Yea, for so much.
9 Then Peter said unto her, How is it that ye have agreed together to tempt the Spirit of the Lord? behold, the feet of them which have buried thy husband are at the door, and shall carry thee out.
10 Then fell she down straightway at his feet, and yielded up the ghost: and the young men came in, and found her dead, and, carrying her forth, buried her by her husband."  (New Testament | Acts 5:7 - 10)

I believe the issue here is not that they "kept back a part of the price", but an issue that they lied to their priesthood leader.  Though giving up the ghost is generally not result when those that lie to their priesthood leader, but they do die a spiritual death in doing so.  Remember the teachings of Jacob -

"Wo unto the liar, for he shall be thrust down to hell."  (Book of Mormon | 2 Nephi 9:34)