The Rolemaster Express PDF is only $5 and it is available from
http://store.ironcrown.com/detail.jsp?itemId=3121169&category=162528
It is based on the Rolemaster Classic rules (and Rolemaster Classic is a revamping of the rules from prior to 1995).
Rolemaster Classic (RMC) is comprised of three core books (there are 2 additional books for GMs, Creatures & Treasures (due out next month) and Campaign Law (due next spring)). The three core books of RMC are Character Law, Arms Law, and Spell Law.
Character Law ---
Not much changed from RM2, however we did add in a number of new options, plus we discovered that MANY (if not most) people who played RM2 actually played with several options, thinking that they were core rules because of how screwed up the RM2 versions of the books were when it came to layout and such. Th organization of Character Law for RMC is a LOT cleaner and easier to understand.
Arms Law ---
We ditched the RM2 tactical/initiative system and put in a completely new system that is both simple yet very flexible at the same time. Basically, action require a certain percentage of activity to accomplish. You declare actions, you roll init to determine order, and then you resolve the actions, short actions first (core rules declare short actions as being under 50% activity, but the flexibility comes in here because the GM could do it in 4 phases of 25% activity each or a single phase or whatever he likes). In each "phase", actions are resolved in init order. Rinse and repeat as many times as required until all activity is used up (actions require a minimum of 10% activity, so you don't get idiots saying "I move 1% of activity", etc..).
Once the round is over, then you do upkeep, things like taking off hits for bleeding, or reducing the number or rounds of stun you have, etc. (yes, it now codifies WHEN this happens, so there is no argument about it. The guidelines also say whether or not a character is stunned THIS round or not when he takes a wound based on the percentage of his activity that he has accomplished...
Spell Law ---
This has the most changes, but the majority of them are less than fully visible, that is because we revamped the Spell Types, getting rid of Passive and adding in a spell type just for illusions...
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Now, Rolemaster Express is based on those core rules. But they are streamlined and so forth.
Here is a RM Express Teaser and a Sample Character that you can download --
http://www.ironcrown.com/free_downloads/RMExpress_Teaser.pdf
http://www.ironcrown.com/free_downloads/SampleCharacter.pdf