Baidu know, community forums, QQ groups, these are free, but also need to spend a lot of time to do the businessman,
First of all, you need to do a good job of updating and maintaining the site, the site rankings will slowly come up, and the traffic will be more,
Related forums to send out the soft and comments,
To the large site to make a pitch,
Deep into the QQ group and the group members mingled, indirectly promote their own sites
These are not so easy, but it is cheaper than BD promotion.