You need to get an alignment after lowering your car regardless of whether or not you have a camber kit. If the alignment shop says you need a camber kit, get one. It would be much easier to buy and install the camber kit with the springs, but if you are tight for money, the best option is to wait and see if you actually need it.

And toe does kill tires, not camber. Negative camber is not necessarily a bad thing. Daily driving camber isn't so good since it looks bad and will degrade handling but for certain types of racing, negative camber is required.