Best economy grade clear, arlon 4500G Clear (gotta specify clear, also comes in trans white).
Best cast clear for the price is arlon DPF 6000RP Clear.
Matte print media is kinda silly. You want to run a matte laminate over what you've printed to achieve a consistent finish. Arlon also makes a fine laminate, their satin is closer to 3m's matte, while their matte is super flat. 3420 satin and 3220 matte are what I keep handy, 3420 for general and 3220 when cast is needed.
Still haven't tried substance out personally, but hear plenty of folks liking it.