The Neti pot looks to be the exact same idea as the plastic wash bottles...it just looks like it can double as a gravy boat when not in use ; )

Here's the one I have:
http://www.walgreens.com/store/product.jsp?CATID=308896&navAction=jump&navCount=0&nug=VPD&skuid=sku2598244&id=prod2598807

It's $12.99 for the bottle and 50 packets (so 50 uses) of sodium chloride/sodium bicarb. When you run out of packets you can either buy them in 100 packs separately from the bottle or mix up your own juice. Just add salt and baking soda to a gallon of distilled water...pretty sure it's 8 tablespoons of each but I'd have to dig out my recipe to be sure...