What car do you drive?
Cars with McPherson Strut in the front can have the camber adjusted slightly by adjusting one of the two huge bolts (also called the camber bolt) that is holding the knuckle with the strut. If you want more camber you have to get adjustable suspension mount. I'm not sure if there's any that can be used with stock absorber as most come with adjustable suspension. If you're using double wishbones like the old Hondas from the '90s, I guess you have to get an adjustable upper control arm, there's no other way.
At the back, you're using multi-link like those in Wira, Waja or Civic EK/EG, you can add some positive camber by using the 'washer trick'. You can google that up for more info. This is usually done if you've lowered the suspension and having problems with too much negative camber. If you want to add negative camber, you'll have to get camber kit for the rear, no other alternative. If you have torsion beam at the back like myvi or viva, you have to stick with what the manufacturer gave you, that is 0 degrees. Unfortuntely.
By the way, my front camber is -0.55 degree. I have double wishbones in the front, so I had to get adjustable upper arms. Another reason I got them was my upper arm bushings are blown and I think this might be a good time to get the adjustable ones since I planned to install lowering springs at the front. At the rear I'm not really sure, but I think somewhere between -0.50 and -1.00. The rear arms are standard.
As far as I know, for cars with rear multi-link, the rear camber is set more negative than the front to prevent understeer and introduce oversteer so that it's safer to drive (for 'novice' drivers).