I was writing something about ammunition expenses in Mechwarrior Online (each individual Artemis Long Range Missile costs 334 C-Bills; each Gauss round is 2000!), but then Piranha Games had to go and ruin everything with this news.
As of the eighteenth of December (which it already is here ion Australia as I write this, but isn't quite yet in Vancouver, where Piranha are), repair and re-arm costs are going away, completely.
So install XL engines and expensive-ammo-ed weapons to your heart's content! You'll still have to pay for ammo when you first install the weapon, I think, but no longer will you be installing extra ammo bins so that the free 75% reload after a game will give you enough to get along, without paying a fortune for that last 25%.
Newbies will get a lot more money - a "Cadet bonus" - for playing their first 25 games, so they can afford a reasonable 'Mech quickly. And trial 'Mechs will now earn as large a C-Bill and experience point reward as owned 'Mechs. So when you buy your first 'Mech you may already be able to afford an efficiency upgrade or two. You still can't upgrade or modify trial 'Mechs, but now they'll just be normal 'Mechs with I presume the traditional lousy setup, rather than complete second class citizens.
Oh, and non-newbies will be getting about eight million C-Bills, the total Cadet bonus, just as a present.
Rewards for starting a game and just standing around doing nothing are now very small. Rewards for killing enemies are much higher. The money and XP reward for assisting in a kill was until now the same as the reward for kill; now you will actually get quite a lot more of a reward for assisting than for being the person who fires the killing shot!
Also, rewards for capturing the enemy base in Assault games are now zero. So nobody will be shouting at the rest of their team to leave the last AFK baddie standing there and capture instead. Capturing is now just a way to end a game when you can't find, or don't have time to get to, the last enemy.
(You will of course get rewards for capturing things in the upcoming Conquest mode, since that's the whole point of that game mode.)