You can get a 1000w in that price range, I say it's way too much money just look on craigslist and you can find 250w warehouse lights like that is made from for $25. I've gotten truckloads of them for free up to 400w but usually they are under $40 for used 400w warehouse ballasts.
You are paying $75 extra for the 5 minutes of work it takes to make one remote ballast like that. And you could find even a dedicated 250 grow ballsast for less on craigslist if you are too scared to wire it yourself.
Just make sure whatever you get is for the right voltage (110 or 120) if that's what you want.