With no pictures and only $250 I'd be suprised if it is a heavyduty enough of a blade for your tractor.
For ditching, I think you are going to want Tilt AND offset. Not sure what your budget is, but everything attachments just came out with a 6-way blade that will angle, tilt, AND offset. Would be a good match if you can swing the pricetag. Everything Attachments Xtreme Duty Tractor Scrape Blade
And even if you do find a good used one heavy enough for your tractor, 8' wide, and having tilt and offset, it aint gonna be cheap. At least not $250 cheap.