Texas officials say they've gotten hundreds of complaints about price gouging and scams in the wake of Hurricane Harvey.

One convenience store in Houston reportedly charged $20 for a gallon of gas, $8.50 for a bottle of water and $99 for a case of water, according to the Texas Attorney General's office.

The state has received 684 complaints in all, according to Kayleigh Lovvorn, a spokeswoman for the office. The agency has started looking into nine cases so far but expects more.

Related: Live updates on Hurricane Harvey's aftermath

U.S. Energy Secretary Rick Perry on Thursday said that even though gas prices will increase because of supply issues, retailers should be wary of inflating prices unfairly.

"Every state's attorney general will be watching to make sure that there's no price gouging going on," he said, adding that all who are considering raising prices inappropriately "need to watch out."

Parts of Texas remain under inches of floodwater and experts predict a lengthy recovery. Thirty-nine people have died because of the storm.