It's definitely a tricky question to answer, and there are a few ways of going about it.
I'm a big fan of Page One Power and they do charge by hour blocks, which you've mentioned. The reason Jon Ball says they do this is because every site is different and they can't charge by the link because of that. A link is not a link.
On the flip side:
- One of the most well known internet marketing firms that employees high profile SEO speakers charges $500 per link.
- A UK link building agency that is medium-well known was charging around $125 a link in 2012
- A large multi-media agency based in California I know of was charging $750 a link on old domains in deep pages for their clients
In my opinion the most transparent way all around is to do it in the hour-block method that Page One Power does it because all links are not created equal. In this method the link builder should report to the client at the end of the month how efficiently they spent the clients money in the 20 hours dedicated to link building that month. This method could cause initial strain in the client-consultant relationship however because the client might look at the consultant's rate (say it's $100 an hour) and compare them to other consultants.
Another method is to charge by the link. The problem with this is all links are not created equal. The consultant is not incentivized in the short term to spend 5 hours to earn one extremely valuable link if they're not going to be paid any more than if they spent one hour building that link.
A hybrid method could be to charge the client based on where the link was placed, but evaluating the price of each placed link every month is a lot of work and a lot of discussion.
In 2014, creating super high quality content should be talked about in the same sentence as building links since they go hand in hand. So that brings us to another method, where a block of say 20 hours a month for a small-medium business is set aside to spend on content and links. Some months 70% of that 20 hours is spent on building that content piece, but then for the next 2 months 70% of the time is spend promoting that content piece. This is how I would prefer to work, and it's a win-win both ways. The SEO consultant is both incentivized to create good content and promote it at the same time. The client is ensured that their money is being spent wisely and for the right reason.
I like talking about prices, it's something we need more guidance on in this industry.
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