$20 sounds like a great bargain to me - the cheapest I have seen it in the UK is around £15 which is more like $30.
As for the controls... you have several options. You can use it like WiiSports Tennis, or use the wiimote like a NES controller sideways, or use the wiimote along with the nunchuck.
"Of course, the main difference in the Wii version is in its controls. In SEGA Superstars Tennis, you can play three different ways. one, the Wii Tennis way where you simply swing the Wii remote like a racquet and let the computer do all the running. This mode works well and keeps the casual gamers on the level of the more hardcore players. I.E Grandpa can now play against Jr. in the same game using the Wii Tennis controls while Jr. plays the more traditional route.
There are two "hardcore" controls. One is with the Wii remote exclusively in classic NES pad configuration. You don't swing the remote like a racquet, and in my hands-on it didn't seem like the motion sensor was even being used in this configuration. You may lose analog aim this way, but it absolutely works well, and I'm guessing this will be the way the Nintendo DS version will feel when I get some hands-on time with the handheld version later this week.
The second way is probably what most people will use: Wii remote and Nunchuk combination. Players will move their chosen athlete with the analog stick and hit the ball with the Wii remote using different motions. Adding the A or B buttons during the swing will alter the type of shot used, and you can also change the aim of the shot pushing the analog stick in the proper direction."
