Kaliakra, if you're looking for inexpensive covers, try DiaperSwappers. There are usually lots of used newborn and small covers for sale. Buy a few different kinds so you can experiment. I bought all my newborn supplies on DS and have covers from Blueberry, Thirsties, Bummis, ProWraps, Sweetpea, and a couple of other companies. I also got my newborn GMD prefolds, some newborn workhorses, and my small Imagine bamboo prefolds on DS.
The GMD website has galleries showing how their diapers fit under various brands of covers, so if you're thinking of going with workhorses, I'd look there for recommendations.
If you're buying new, I really like Sweetbottoms Baby Boutique. Great customer service, free shipping on every order. I've also had good experiences with Nicki's and Diaper Junction.
Cianci, having used both pockets with microfiber inserts and natural fiber prefolds/flats, I can tell you that the latter are definitely easier to deal with in the laundry room. I love being able to wash everything in one load in a single cycle, pull out the covers, and then throw the rest in the dryer.