You can probably sand off most of the rust on thr easel, but the, you'll have to repaint it in that same yellowish color. There are also some good deals on "the bay" for them. The Durst is a prety darn good unit, specialy for free. What lens (if any) came with it? Free is always good!
So what if its an entry level enlarger, for what you paid for it, its a good starting point. A little clean-up and start printing. We all started somewhere, my first enlarger was a 1940's era diffusion machine that I had to make a negative carrier for. Use it, and keep an eye out for a more versatile machine.