[quote name='jer7583']Looks like I won't be buying them then, lol. Used to be maps would go free after a certain amount of time..[/quote]
Not used to be...., it was once, unless the map and specifically dedicated as a free map (i.e. Cold Storage).
For those keeping score, let's recap:
Heroic Map Pack (Standoff, Rat's Nest, Foundry) - Released at 800 MSP, Free after LMP release.
Legendary Map Pack (Blackout, Avalanche, Ghost Town) - Released at 800 MSP, 600 MSP after Summer.
Cold Storage - Free at release.
It's hardly enough to discern a pattern, but if I had to guess, I'd wager the following, taking into account Bungie's statement that "The Legendary Map Pack would not become free":
Legendary Map Pack - Stays at 600 MSP (No reason to drop the price AND give LMP-specific achievements).
Mythic Map Pack (Assembly, Citadel, Heretic, Longshore, Orbital, Sandbox) - 1200 MSP (30 Achievements, 6 Maps, a new ranking system, and several new playlists...that's a LOT to throw into a single update. With everything coming out and a large dashboard overhaul, I imagine there's going to be so many new features, that 360 owners will be dropping their pants and 1200 MSP rather easily).
A more conservative estimate would be MMP at 800 MSP, but I believe Bungie could easily get away with 1200.
~HotShotX