How does it work? Do you pay an x amount (budget) for the month to the link builder and then they buy the links/posts the budget allows.What about pay for their work? I am thinking about getting a link builder on a freelancer site.
Why not, I would suggest hiring somebody first to get a list of all blogs with pr in your niche. Then get another Virtual Assistant to then spend comment on 5-10 per day with high quality responses and document everything so you can check these sites if needed to check their work. Get on oDesk or Freelancer and pose your request for workers and see the response and how much people are willing to take to do the job you need.
If you have low amount of sites you will do better by just pucharsing links. I can suggest you some cheap and quality source of backlinks, if interested - pm me.
It would be good idea if you hire virtual assistant and get work done according to your specifications.
just find a good service provider and outsource your work, pretty simple. some service providers offer packages which you can subscribe to where others do what you tell them to do. cost also vary from one service provider to another. try to find someone who has good experience and has some reputation. and remember one thing, you get what you pay for. if someone quoting you cheap, it usually means you will get cheap work. good service providers knowing their work don't usually work for cheap as their services are in great demand.
it will be better if you can break down your budget in each section, for example, x% of the budget is on the blog post, x% of the budget go to the social media, and x% of the budget invest on sitewide link etc. Then, you can actually save some money compare to just pay x amount to the link builder