Okay so I came across this story a couple of times a while ago on ffn and wondered if it was over here. Humans and demons live in the same society. Kagome's family was killed and she was made into a slave by Naraku at a young age. She's mostly used as a sex slave and there is some kind of spell or charm that keeps her obedient or something like that. Inuyasha sees her on sale in a market and decides to buy her because she looks just like his dead mate Kikyou, and Sesshomaru decides to buy her before he does just to keep her out of his hands and not have her turned into a literal copy of Kikyou. Sesshomaru doesn't approve of slaves and he has her live with him so he can get her use to living a normal life before he frees her, but Naraku is after her since he was able to 'visit' with her with her other masters. When he realizes he can't do that with her new master he decides he wants her back. Of course over time Sesshomaru and Kagome fall for one another. They make a visit to his castle when his house is damaged in an attack by Kagura and meet a relative of his who decides to play match maker.
Let's see..other details....Sango and Miroku are in it and they have their usual professions. Sesshomaru hires Sango as a personal bodyguard for Kagome after he finds out that Naraku is after her. Shippo is around..only older and Sesshomaru has him get information for him. Kouga makes an appearance as someone interested in buying her when Sesshomaru takes her to work with him, and Houjo is mentioned as someone who had owned her at one point and works for Sesshomaru.
I hope that's enough details to help with the search. Whether it's here or on ffn it doesn't matter.

I found it! It's located on ffn and is called Bonds of Slavery by: Child of the Ancients.

Kagome has been a slave for 9 years and has given up all hope. Then, one day, a handsome inu youkai buys her with the intention of setting her free despite all the problems.
Rated: Fiction M - English - Romance/Fantasy - Kagome H. & Sesshomaru - Chapters: 25 - Words: 71,037 - Reviews: 1,069 - Favs: 575 - Follows: 62 - Updated: 12-10-03 - Published: 09-10-03 - Status: Complete - id: 1514886

http://www.fanfiction.net/s/1514886/1/Bonds-of-Slavery