My 2006 Prius Died...Junk/Fix/Sell?

I was driving the other day, and all of a sudden it started with this horrible knocking sound. I have never heard the sound before. I remember back in the day, with a 67 buick rivera, that if the oil got low, the engine would knock, and this kind of sounded the same, but more high pitched and clicky. I checked the oil first thing and there is plenty in there - in fact, I had just checked and put oil in it about two weeks before. Please note, that I have not always kept up with the oil changes, and sometimes the oil level was pretty low. My sons tell me that the sound seems to be coming from the top of the engine, and it's probably toast, a rod knock. I parked it, and figured i will get it looked at in a few months, when i'm better able to pay for diagnostics. I'm asking for advice, on whether or not I should just junk it or sell it, because the batteries are still in good shape, and i know they are pretty expensive. Any advice would be appreciated. Thank you.