Will not start

I have a car that will not start. It just continues to turn. A mobile mechanic checked and says his computer shows the "throttle body" needs to be replaced $660.00 (part) from the dealer. He says, it is showing 50 instead of 0 on the computer. Could a throttle body make the car have trouble starting? I want another opinion because we just survived a Texas storm and I do not have money to waste.