You can always substitute dumbbells for barbells (FYI: both dumbbells and barbells are "freeweights"). When doing squats and lugnes, you can hold the dumbbells at your shoulders (I bring them up to a hammer curl and a little farther and hold them in front of my shoulders) or at your sides.
When you do substitute dumbbells for a barbell, don't be surprised that the total weight you can lift is less (ie: if you can lift a 30# barbell with a specific exercise, 2, 15# dumbbells will probably be too heavy, because you have to stabilize more when using dumbbells, and the strong side can't help out the weak side).
One workout that uses only dumbbells is PUB (though PLB uses a barbell--you can always substitue, though!)