How much should I charge him?

I have a client that wants me to set up Volusion on his website and link it to Doba.

I once made a website for him and added a few things, it ended up being $170

How much do you think I should charge him for this? I think he'll back out if it's too much.

Any opinion is greatly appreciated.

Thanks

I would price to a similar basis as you used for his first job - as that looks as though it was OK enough to get you the 1st order