Is it wrong to sell food, books, candy, drinks, etc. in God's house to raise money to go on trips or to help buy the things the church needs?
Your question is actually backward. You should be asking if it is right to do those things. Since God told us that "as His divine power has given to us all things that pertain to life and godliness, through the knowledge of Him who called us by glory and virtue" (II Peter 1:3), then we conclude that God has told us everything that we should do in regards to life and godliness. If we can't find justification for doing something, then we ought not to be doing it.
What we are told is that churches are to raise their funds through voluntary contributions (I Corinthians 16:2; II Corinthians 9:7). There is no command or example of churches raising money in any other manner. See "Is it right or wrong to sell inside the church?" for additional comments on this issue.
There is even a strong hint that God does not like the mixing of secular ideas with His worship. Remember Jesus throwing money changers and sellers of sacrifices out of the Temple area? Take a look at the answer: "Can a bake sale be held at a church?" for a detailed discussion of this issue.