How much should a design Enginneer ask to do contract work?

[Tigger1]

DH has been laid off for several months. He is hoping to go back to work for the company that laid him off but they are not allowed to hire back yet. There is a mention of doing contact work for them. DH has not done contract work and is not sure what he should ask for per hour. We live in Oklahoma, a state that has lower wages than most states. He was making in the over $40,000 per year befoe he was laid off.

Any suggestains what to charge $$ per hour ??

Thanks Tigger