Judges 11

then it will be that whatever comes out of the doors of my house to meet me, when I return in peace from the people of Ammon, shall surely be the Lord’s, and I will offer it up as a burnt offering...Then she said to her father, “Let this thing be done for me: let me alone for two months, that I may go and wander on the mountains and bewail my virginity, my friends and I.” vv.31,37

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No where in the Bible is there actually a human killed for an offering to God.  Yet this passage is used to show that it is by many Christians today without looking at the actual words used in this passage.  (The other reference in the bible is of Abraham's offering of killing his son Isaac, but this was just a test by God to test his faith, yet God did not allow him to actually do it.)  When Jephthah is making a vow to the Lord that if God delivers the people of Ammon into his hands he will make an offering to the Lord.  Yes it does specifically say burnt offering but it doesnt specifically say "and."  This word and can also be or in the Hebrew which therefore shows that Jephthah is saying he will make a dedication to the Lord or a burnt offering.  Jepthah sure probably considered that his daughter or other kids or wife could easily have come out to meet him, probably more than an animal would come out the doors to greet him, so wouldnt have thought he'd kill them as an offering.  Then what does it mean to dedicate a person to the Lord?  Well we see later in the chapter that both his daughter and he knows exactly what it means: perpetual virginity.  Multiple times is the word virginity used as she goes with her friends to mourn her virginity and that she never knew a man (v.39).  No where do we read of Jephthah killing his daughter but fulfilling his vow.  This for sure would be an offering as it would be hard for any father, then or today, to not see their daughter married as well as a girl/woman's desire to marry never be fulfilled. 
What kind of dedication can you imagine making to the Lord that would be hard like this?