If the guy is good and gets you a scalable and easy to maintain site, for $70/hour, you got the best deal in town.
Let's assume 50 weeks of work, at 50 hours a week, or 50*50*70= $175,000.
The site will incude a database, framework, dev and prod environments, automated deployment, an admin interface, an API, templates, css, jQuery, and a good-looking site.
If you tried to hire the skillset for that in a regular company, you would be looking at
- DBA: 95K/year
- Sysadmin: 80K/year
- UI Engineer: 75K/year.
- PHP Developer: 60K/year
- Project Manager: 75K/year
...for a total of 385,000 in salaries. Multiply by 1.5 for the overhead (Employer taxes, health insurance contributions, office space rent (these people don't work in dusty warehouses), 401K, computer equipment, hiring costs (your HR person isn't free), etc) and you're looking at $577,000.
Now, I guarantee that the project won't be done in a year. It will take 2 months to ramp up,
2 months to get the servers up and provisioned (I'm being optimistic in my estimates), 2 months to nail down the requirements (with the team in place, can't write it all down and expect people to read it. You need meetings.), 2 months to design a passably scalable system, 8 months of coding, 2 months of testing, 1 months for deployment... Oh shit, I forgot, you need an architect for the scalability part: $135,000/year--No? Ok, no architect.
So we're looking at a minimum of 19 months. The bill is now $ 912,000
That's assuming nothing goes wrong, meaning, nobody leaves the team halfway. What happens if your PHP coder leaves at 90% completion of the framework? (Knowing full well the remaining 10% takes another 90%) and, huh, you gotta pay salaries to the rest of your team while you find a competent PHP developer who is willing to take over the custom framework-from-hell. Let's say you're lucky and you find this guy, and I'll be nice and say you can hire him and put him in a cube in 2 months. By now, though, you're paying $100,000 for the php guy--you learned from your mistake. He takes 2 months to familiarize himself with the project, go over the code base, and learn the server setups. That's not a lot of time. 40 business days. So this adds 4 months to the schedule.
So the interim 2 months period cost you: $81,000
His 2 months ramp up period cost you: $106,000
So, realistic scenario: your website cost you $1,100,000, and takes 23 months.
And if you look around and ask people who have done this stuff, you will find that I'm not out on left field.
So at $175,000 your guy is providing the site for 15.9% of the normal cost.
Imagine if he charged you $300 an hour. That would be $750,000, and gets done in 1 year. You would still save a 350,000 dollars and have your site done a year earlier.
If the guy can deliver, he's worth 4 times what you're paying him.