Any sharpening stone is a "whet stone." To whet, means to sharpen.
There are many kinds of sharpening stones. The two most common kinds are "oil stones," and "water stones." Most strong, hard knife alloys (strong and hard are terms of art) sharpen significantly more efficiently on water stones than oil stones. Many tough, soft (also terms of art) alloys sharpen slightly better on oil stones. If you're only going to buy one set of stones you're probably better buying water stones.
Water stones come in all sorts quality and price levels. The rule of thumb is that you might not get what you pay for, but that you certainly won't get what you don't pay for. There's enough knowledge on this forum to guide you to a good set of stones.
Water stones and oil stones work differently from one another. The primary difference is not the kind of liquid either. In fact, oil stones are almost as commonly used with water, soap, soapy water or dry as they are with oil. I use two synthetic and two natural oil stones; almost always using them dry, and never with oil.
Whether oil or water, modern synthetic stones are made by mixing an abrasive and a substrate and baking them into a stone. Water stones use water-soluble substrates, oil stone substrates are not soluble. When water stones are wet, the a continuing supply of substrate and abrasives come off surface of the stone in the form of "mud;" and it is the mud which does the actual sharpening.
Oil stones use textured and slightly porous surface of the stone. Oil stones rely on liquid to "float away" the "swarf" and keep the stone's pores from "clogging.
A good set of oil stones costs less than an equally good set of water stones. But, as I said, if you're only going to have one type you probably want water stones.
Synthetic water stones come in a variety of different types. Besides the coarseness of the grit (you'll need at least two, to begin with), the most obvious distinctions are the type of substrate (aka "binder"), the type of abrasive, and the density of the abrasive. Clay is the cheapest substrate (the stones are often called "mud binders), then resin, and then magnesia; and as a general rule, the more abrasive in a stone, the better the stone.
My water stone kit consists of two resin binders, and two magnesias.
Sharpening Supplies is a fairly good retailer but they only stock a limited selection of water stones; and if you ask them for a recommendation they'll -- of course -- recommend their stock. I happen to like the Naniwa SS stones they carry, but there are lots of other possibilities; some of which may be better for you. Although you may end up purchasing from somewhere else, Chef Knives to Go has the best online selection of water stones on the web.
But let's hold off on specific stone and retailer recommendations for now while you familiarize yourself with the range of possibilities and prices.
Sharpening freehand on bench stones is one good way to sharpen, but it is not the only good way. The best way for you will depend on what kind of person you are and on what kind of knives you'll be sharpening.
For some people, electric sharpeners are indeed the best way to go; so it's a good thing that not all of them are not knife eaters. Chef Choice electric sharpeners aren't perfect, but they aren't bad either as long as you use them properly.
For a lot of people though, a good "tool and jig" sharpening system such as an Edge Pro or Wicked Edge is the best combination of easy learning, convenience, and edge quality. Unfortunately, good toll and jigs run expensive. But if you can afford the initial outlay you should certainly consider using one.
At the end of the day sharpening is no more complicated than rubbing a piece of steel against a rock. But there's an awful lot of minutiae to get out of the way before things get that simple. There's a start. Now it's up to you. Ask lots of questions.