Good afternoon all

I brought my 2009 RX350 to a NAPA for regular maintenance. When I got it back, I noticed a scratching sound coming from the engine. I thought it was just the weather. I eventually took it back because the sounds wouldn't stop. The mechanic pointed out a hole in the valve cover. I woudnt be surprised if they damaged it because it was a shiny hole. Regardless, I'm looking for a cheaper fix. The part 112020p020 is going from $350-500. I'm wondering if I'd be better off taking the cover off and putting a TIG welder to it, or selling the car as is. What are your thoughts?

Thanks in advance