Can SEO ever be cheap?
 

Over the years I have come to realize that cheap SEO services don't exist. Or at least "good" cheap SEO services don't. How would you design a SEO budget on $500?

Its a good profession don't use it as a business

It's difficult to say...

Obviously you can price per keyword but some will be higher competition than others so will involve more work.

In my opinion you should take a look at their needs and make an honest quote which revolves around what you're willing to do for that price.

SEO isn't quick as you know so $500 isn't a lot to ask for. If someone isn't willing to pay at least that then move on and find someone else.

Honestly I wouldn't do SEO for less than $1,000 per client per month.