Niche Backlinks
 

How many Nich backlinks are ok a month ?

We are property renting agency in London
How many backlinks you think should be ok to get a month.
We are willing to buy one strong backlink from high pr website (related content)
Some press releases and few blog post a month matching our business
I am not really sure if we should buy blog commnets as it result just as a damage (i think)