Right...I don't think so. I can't fathom any human in any period of time thinking that volunteering themselves for slavery was a good idea. But, Christians seem to think that this happened all the time. There's a term for this strange phenomenon within Christianity. It's called Christian reimagining. "He who controls the present, controls the past." -George Orwell. Basically, Christians like to rewrite history so that they, and their god, come out looking good, or at the very least, so that they don't come out looking like the moral depraved monsters that the bible and their god would suggest that they are.

Now, the very notion that slavery was voluntary is ridiculous. There are so many verses in the bible that plainly state that it clearly was not.

Leviticus

25: 44-46 However, you may purchase male or female slaves from among the foreigners who live among you. You may also purchase the children of such resident foreigners, including those who have been born in your land. You may treat them as your property, passing them on to your children as a permanent inheritance. You may treat your slaves like this, but the people of Israel, your relatives, must never be treated this way.

This hardly sounds like a voluntary situation to me. It sounds just like what slavery is as we now know it--humans buying other humans as property. And here's what Exodus says about Hebrews, specifically, so not only is this not voluntary, but you have no control over it if you are a certain race, are a wife of a slave after the fact, or were born from parents that were married after the male became a slave.

Exodus

21:2-6 If you buy a Hebrew slave, he is to serve for only six years. Set him free in the seventh year, and he will owe you nothing for his freedom. If he was single when he became your slave and then married afterward, only he will go free in the seventh year. But if he was married before he became a slave, then his wife will be freed with him. If his master gave him a wife while he was a slave, and they had sons or daughters, then the man will be free in the seventh year, but his wife and children will still belong to his master. But the slave may plainly declare, 'I love my master, my wife, and my children. I would rather not go free.' If he does this, his master must present him before God. Then his master must take him to the door and publicly pierce his ear with an awl. After that, the slave will belong to his master forever.

Obviously, the person being bought, as is clearly stated at the very beginning of this excerpt, has absolutely no will, unless he chooses to remain a slave after being set free so that he can stay with his wife and kids. Well, how very gracious of the Christian god to allow for that much.