How much should I do on my own?

While it is not the popular answer, the best one is … very little. Most states and municipalities allow homeowner to perform basic handyman tasks in their own home. That being said, it is still risky to do most electrical work yourself.

It seems expensive

Contact several contractors. Get more than one estimate. If a contractor doesn't want to give you an estimate, they aren't that interested in your business. Forget about them.