I agree with the others but can offer one local option. STAMPA, the Irish National Stamp Exhibition, is 6th to 8th October 2017 at the Griffith College Campus, South Circular Road, Dublin 8. See
www.stampa.ie. You can take the whole lot there and talk to a couple of dealers. Consistent with the other posts here, I predict you will have no offers, or an offer of perhaps €50 for the lot. Dealers can only pay €0.01 to €0.05 per cover in bulk because they have to sell at a profit and the selling price will be €0.10 to €2.
Normally it is best to go in the afternoon, or on the 2nd or 3rd day. In the morning of the 1st day, dealers want to sell to others to make back their costs of attending, not buy from you.