Believe it or not, I bought a whole set of 3/4" drive sockets just because I needed this size, and it was relatively cheap at Harbor Freight. I'm really glad I got it, instead of just a single socket, because it's come in very handy for all kinds of things.
Whatever you get, remember that the nut is pretty thin, and a lot of large sockets have a rounded edge--then you get little "bite" on the nut. Look for one that has a relatively sharp edge, or buy a cheapo and plan to grind it a bit.
Ain't Spridgets FUN?