Those gimmicky TV advertising fitness machines are a crock of you know what!
Join a gym ;)
OR, you can do a lot at home as well. On the days that I don't go to the gym for whatever reason, I do a lot of leg work at home.
Stand with your back and head flat against a wall, then walk your legs forward until your thighs are parallel to the ground - you should look like you're sitting on a chair. Shins should be at right angles to the floor. Now hold it for as long as you can! When you can't hold any longer, get up, shake them out for 30 seconds, then repeat. Try to do at least 3 reps each time.
Squats are very good, preferably with weights - which is why the gym is good.
If you don't have a weight bar to chuck over your shoulders, try this one.
Bend your knees into a squat, keeping your back dead straight. Stick you bum out behind you, and lean forward slightly at the same time, holding your hands together and pushing them forward level with your shoulders. Your feet should be about a foot apart. Do as many as you can, and same as above, rest for 30, then try again. It won't hurt too badly now, but the next day you should feel it. Squats are GREAT for toning up your legs.
The other one is lunges - the bane of my existence. My PT had me doing lunges in our session this morning with 15kg kettle bells in each hand.
Doing it with weights is best if you want good results.
Start with your legs together, arms by your sides. Then take a long step forward. Bend both legs until your back knee is nearly touching the ground, then push off and repeat on the other side. I do about 30 steps in each direction, with weights, then go off and do another exercise before coming back to them for 3 more reps. Now they really hurt the next day!!