That's what I'd do. There really isn't a decent-quality option that would cost less, as far as I'm aware, unless you can find a used one at a bargain price. And even then, you're probably not going to save huge amounts over the price of a new one if the lens is in good shape. On the other hand, a used lens may be the way to go. I'd guess that fisheyes probably have more turnover than most other lenses, because a significant number of people buy them and then realize they don't use them very much once the novelty wears off. For some of us here, the novelty may never wear off, but a fisheye isn't to everyone's taste. So there might be a larger used market for these. Still, lenses tend to hold their value pretty well. The only real exception is when a new model with more features or better quality is released at or near the same price as the previous model. But that happens relatively rarely with lenses, and the prices still don't drop through the floor.
That's a good decision; the waiting is always a pain, but I can virtually guarantee she'll be much happier with the pictures she'll get from the Rokinon. And yes, there's no shortage of sticker-shock when you go shopping for lenses (I haven't found a worthwhile hobby that's cheap to pursue, sadly). I'd like to have a fast telephoto zoom like a 70-200 f/2.8, but the prices on such things are so far out of my reach (for something I can't justify as a business expense of some sort right now) that I can't really pretend to entertain the idea. There are other things I need that are a bit more in the realm of low-hanging fruit.
I say the same thing every time as well. I think that is the sort of thing that scares some people away from interchangeable lens photography lenses that sometimes cost well more than the camera bodies on which they're used. The idea of paying so much for something lots of people think of as an "accessory" seems crazy. But as with speakers as a part of a stereo system, lenses are one of the critical components of photography. Until digital cameras came along, they were far more important than camera bodies. And they're still more important in many ways.I just looked up the price of the 70-200 f/2.8.That's all I've got to say.
