I was looking at the NYX cosmetics and the pigments were $3 and the pressed were $5.50?
Pressing matte shadows is the same as pressing any other shadows. Mix the pigment with alcohol or biosilk enough to make it pastelike and press it in the container that you want to place it in the pan. You are vague with your question so I can't help you out too much sorry
Pressed are easier to work with and less messy, however they cost more to make because they use more energy to be moulded into that form. Imagine if a powder eyeshadow opens in your handbag = NIGHTMARE! lol
they're messy and more difficult to use