Investigators are hoping surveillance video from the Valero on the North Freeway near Airtex will help them ID the suspects.
Harris County sheriff deputies say two men with guns drawn and their faces covered with ski masks ran into the store.
Authorities say one of the suspects slid across the counter and pointed the gun at a female clerk. But when she didn't move fast enough for the suspect, the store manger says one of the armed man pistol whipped the clerk. They took off with an estimated $2,000 in cash.
The news of the robbery and violent attack has customers and potential employees scared.
"That's a terrible thing. You can't even work anymore without somebody trying to rob you," said customer Doris Jenkins.
"That's wrong. People like that will burn in H-E-Double-L. That's just wrong," said customer Robert Flores. "It's a bad time of the year to be doing that. I know the economy and stuff but people just need to get out and work."
"The worst people come out at Christmas time and I don't know. I'm sure I'm going to get hired," said concerned citizen Deborah Rinehart. "I did put in an application to work here but I don't know. It's kind of strange and scary."
Surveilance cameras are set up inside and outside the store. The store manager says the robbery and assault was all caught on video. Sheriffs deputies are now using that video to try and track down the robbers.
The store clerk was taken to the hospital with minor bumps and bruises.