Gadgets

Dragon Radar
The Dragon Radar was made by Bulma to find the Dragonballs on Earth, though later used on fake Namek and the real Namek to find the Namekian Dragonballs, it has proved to be a very useful device. 

Flying Nimbus
Flying Nimbus or Kinton Cloud, is well a cloud, and only someone with a pure heart can ride it. Goku is the primary person to ride Nimbus, but Gohan and Goten were also able to ride it. 

Healing Tank
Saiyan warriors use this machine to heal themselves. This machine fills up with synthetic Saiyan DNA, which heals and raises the Saiyan's powerlevel. Goku uses this after battling Ginyu and before battling Frieza. Vegeta uses this after battling Goku on Earth. 

Nyoibo Staff
Goku's orangish-red staff that can extend to any length upon command. 

Potara Earrings
Earrings controlled by the Kaio-shins, when two people put one on the opposite ear, they can fuse into one powerful being. 

Senzu Beans
Senzu Beans, are small green beans grown on Karin Tower. They replenish strength and energy instantly and are used by Goku and the other Z Warriors many times. 

Scouters
Scouters are small mechanical devices that fit over your ear and are used primarily to measure one's power level. The only beings the mainly use these are Frieza and his henchman, though Bulma does fix one in the Saiyan Saga to read in English. The scouter is also used as a communications device and anyone wearing one can hear what is going on. This is how Vegeta and Nappa learn about the Dragonballs on Earth. 

Space Pod
The Space Pod is what the Saiyans and the Ginyu Force use to travel in space (hinting the name "Space Pod"). The pod is small and round in shape and has one large window in the front for viewing. 

Time Machine
The Time Machine was created by Bulma in the alternate future so that Future Trunks could go into the past and heal Goku's heart condition. It takes about 6-8 months to fully recharge for the round trip home. 

Training Capsule
The Training Capsule is like a modified space pod only much larger. Goku used this ship to train in on his way to Planet Namek. The Training Pod has a device called the Gravitron, so that Goku could train under different levels of the Earth's gravity. The ship also comes with a kitchen, living room, bathroom, and bedroom. Dr. Briefs invented this "gadget".