The magazines are meant to increase your job level, so your peep will get promoted sooner. You have to buy the one related to their jobs, though: if he or she works at the office, you have to buy the office magazine and put it onto the selected peep.
The perfumes are meant for "romance" and some people say it improves baby making. I myself tried that and the only thing they did was celebrate marriage. They also make them a little happier.
And the kit, you can use it to "erase" something one of your peeps dislike. And it is really useful in some particular cases...

The perfume is best to be used on the man as it is designed to smell nice to him so it'll make him happier while the cologne is best used on the woman for the same reason.

If you can find a magazine in the store for your peeps before they complete one work cycle, you can give them an instant promotion to level 2 when you use the magazine on them.