It depends. Contract work through contract services will generally pay a range from $40-$100/hr depending on your location and skill set. They do this because in the end they are charging $70-$200/hr, and they are spending money to find the jobs and place you.

If you instead go the "freelance" route, then your rate would be more along the lines of what a contract agency is charging.

Some advantages of contract services is that many times they will have health benefits if you need them and it only costs you a small amount of money. Also, they will work hard to keep you working and they deserve to be compensated for it. If you instead go the freelancer (independent consultant) route you'll be responsible for finding the work, doing the work and keeping yourself moving forward. Depending on your network the ability to find and keep work is either reasonably easy or damn hard.

Please just don't take your prior salary and divide it by 2080 and figure that is your rate. When you contract you will need more savings, you will have additional costs including taxes to pay etc. So make sure you keep all that in mind.