I hate to say this just after Mom2Katie's post, but I wouldn't buy pergo from Lowe's or Home Depot. The grades sold there are not as good as the grades sold elsewhere. The good stuff there is alright, I just wouldn't support the practices they use for the cheaper grades.
IKEA has very cheap laminate, so does Costco. Having installed the stuff, I'd say the laminate is easy as pie. Doing the trim work in interesting, though. If you already have baseboards, anyone can do it. Just rip those off and lay it, then put the baseboards back, with adjustment cuts at the doors and openings. Without any baseboards to start with, you'll be doing a LOT of trim carpentry. No biggie if you've got experience, but daunting otherwise.
For general floor covering, DON'T do peel and stick tiles, they get nasty on the seams, the adhesive comes through and picks up dirt and looks unclean. The tiles you see in stores are really laid in adhesive, and are not the peel and stick they appear to be. Those store floors require professional waxing, too.
I would recommend getting an area rug at Lowe's or the Depot, they tend to have pre-edged rugs in 11x14 for ~$30, plain colors. You can also get the carpet store to edge a rug for you, any color they stock. That can be a good deal, as carpet is relatively inexpensive without padding and installation. I'm sure they could tell you price on the phone, too. There are many carpet wholesalers near us, End of the Roll, Carpet Cents, etc. We got a remnant and laid it ourselves for about $120, as an example (incl. pad and tool rental).
I have also done a lot of vinyl floor laying. It's easy, too. If you can sew, you can lay vinyl. Get the Armstrong Kit, they will replace the floor if you screw it up (if you buy armstrong lino). Rooms less than 12' (in any direction) are soooo easy, there are no seams. Vinyl is much softer than pergo stuff! Laminate flooring is very very hard. Cold, too, unlike real wood. Real wood is the same price to install as laminate, but requires surface prep. The general rule is real wood for new construction (prep already done and it's level) and laminate for remodeling (little prep required and level is not so important). Vinyl in your living room WILL dent, it's not so good for furniture.
If it's concrete underneath, that complicates things a little, moisture will always come up through a slab floor. You will need to take that into account no matter what you do, but especially if you are using any sort of adhesive. However, doing it is even more important. Concrete + Carpet is a particularly bad combo for harboring allergy-inducing organisms.