Hey man, I am no boxing expert, and am actually getting a garage set-up just like you. I would say stay away from the kits you have mentioned for a couple reasons. First you may not use everything you are getting, and secondly it may be crappy stuff. My advice would be just pick up what you need as you need it. I would also caution you to do your research on what you are buying before making the purchase. I cant tell you how many times I have bought something, then after doing a little more research, found something I would rather have. Also, dont go cheap. You will probably end up replacing it anyway, so make sure you get what you will be happy with in the long run.
As far as what equipment to get, are you woking out solo or with a buddy?
Heavy Bag, (or Muay Thai bag if you are kick boxing).
Focus Mitts, (if you have a buddy, tons of fun).
Belly Pad, (shots or kicks to body).
Muay Thai Pads, (only for kick boxing obviously).