Advanced Specialties has them for $449 and they toss in a good quality DC power plug as well. They've had that DC plug deal since the 500 first hit the market. Best deal around, even though it's only about a 20 dollar extra. I bought my 500 from them when they first came out.
https://www.webtrix.net/shopcart/Adv...ners%3C%2Fb%3E