Technically, it’s called a range extender. My access point is in a far side of the house in the computer lair, so I put one of these in the living room, which is kind of in the middle. Now I have good signal everywhere.
Weird name, but I’ve ordered from Dailysteals, their sister site, and have good service. I’ve had an issue or two but their refunds are pretty prompt and they pay return shipping. For the prices, I keep coming back.
If you have a smartphone, and who doesn’t, using WiFi is much faster and saves your battery. Plus it’s just nice to stay off the cell side so people get better service who aren’t on WiFi, say, in a downtown area.