Well, a quick trip to Ammo Seek is telling me that the off brand 00 Buck is going for about $1.50 per round before shipping. The cheapest Federal I saw listed is the LE Tactical (which may or may not be what you have) at $2.00 per round before shipping. It all goes up price wise from there. None of the local stores I frequent have any.
I hate trying to set prices in a market like this one. Give someone a price that's too low and you're a fool. Give someone a price that's too high and you're a profiteer. Problem is nobody can say if or when ammo prices and availability will be back to "normal". I've sold a couple of things recently at what's "fair market" today. I would have laughed at those prices a year ago. None of the people I sold stuff to complained.
Given that, I could only tell you what I'd sell it for, $200. If you listed it local I doubt it would last the day.