Guard are my second army, but as they say "second on the charts, first in the hearts" (and they do say that, by the way).
First thing you'll notice, is that to field some of the Emeror's finest, you might need a lot of models. A lot of models. It can seem. Like a daunting task at first.
My recommendation is to make use of the 5 man push together box sets. I guarantee that when playing, they shoot with the same ballistic skill. Unless you get as many boxes as you can and make a conscript unit.
I like to use one normal box of guys (in my country about $50) and then pick up two of the 5man boxes (total value of $25) and voilà, two legal squads. Pick up a starting army box ($140 here), and you get some guardsmen, a tank and a Lord Commisar HQ.
8th edition makes out T-shirt saves something, and the humble lasgun is almost on par with the space marine boltgun, and finally a capacit to outnumber many of the opponents by at least 3 to 1 model count. Quantity surely makes up for quality.