Wait a Minute!!
Balancing, and Alignment are TWO Completely different things.
Balancing a wheel means the operator spins the rim and tire combination (known as a wheel

) on a machine and checks for "out of balance". What that means is he looks for a heavy spot on the wheel, and then adds weight on the other side to correct it. This must be done whenever you install new tires on rims.
Shaking between 50mph and 70mph is 98% the cause of an unbalanced wheel.
Getting an Alignment means your having the vehicle checked to make sure that all your wheels are pointed in the right direction and your car is driving straight, and your tires are wearing properly.
*CAMBER*
When you lower a car, you get camber on the wheels (why they looked angled in). If this is not corrected on a daily driver, you will start to wear the inside edge of your tire, causing it to wear out pre-maturely.
*TOE*
When your driving down the road and your car like to pull to one side, or your car is "crab walking", aka driving straight but your body looks like its angled this is because the toe alignment is off. Driving with lots of toe will cause the tire to have a shaving effect and will greatly reduce the lifespan of your tire.
It is a good practice to spend the money to align your car once a year, depending on how bad the roads are and the amount of stress you put on your car by lowering, etc.
Many alignment shops offer the ability to CHECK your alignment for say 25$, and then if it needs correcting they will charge you the extra 40$ or whatever it may be to fix the problem.
If you've lowered your car you will need adjustable arms in the rear to fix the camber wear. Rear toe is Factory adjustable, front toe is factory adjustable.
That being said...
Wait until your suspension is on, and your wheels are on, and two weeks before you get an alignment.
And Camber will kill tires also, but toe will kill them almost double.