Looks like a nice flat top there.
My 066 red light cost $400 with a KS jug.
My o64 was $360, but I had to rebuild the carb and replace the coil. Somebody beat that saw with an ugly stick before I got it. It's no princess.
What bar and chain you can get with saw makes a big difference too. Bars aren't cheap. Multiple bars or chains can easily raise the price by $200 and still be worth it.
There are some horror stories of the 661s heating up and dying. The diagnosis ranges from bad solenoids, to full carb replacements, to faulty control modules. Mtronic issues that are difficult to diagnose without swapping expensive parts. There's a thread up on tree buzz about it right now. I know a lot of people are really happy with these saws and have no problems, but if you get a lemon out of warranty you're going to drop a lot of coin to fix it.
I'm not trying to pick a fight here. I do not own a 661. Partially because I have read others' complaints, partially because I like old saws, and mostly because they're pricey. I really want one from Tree Monkey...