for sale
When a character is being sold or bought.
Often, but not always the character in question is a slave.
This tag should only be used if ownership of a character is for sale. Cases were sex acts are for sale should be tagged with prostitution.
If the character is a slave the slave market or slave_auction tag may be appropriate depending on the setting.
The price tag may be appropriate if a specific price is listed for a character.
The price_tag. tag may be appropriate if the character has an attached price tag.