Backlinks的网址 http://www.backlinks.com/
PR和链接价格表：
PageRank (PR) 1 homepage $.50 , subpage $.50
PageRank (PR) 2 homepage $1 , subpage $1
PageRank (PR) 3 homepage $2 , subpage $1.50
PageRank (PR) 4 homepage $3 , subpage $2
PageRank (PR) 5 homepage $4.50 , subpage $3.50
PageRank (PR) 6 homepage $12.50 , subpage $10
PageRank (PR) 7 homepage $30 , subpage $25
PageRank (PR) 8 homepage $75 , subpage $50