In my article below, Chumby made the following comment:
"And hey, let them benefit from their armor, it's not like they don't pay for it."
So, I thought we should have a little look at this claim, see to what extent it's the case...
For a baseline, we shall start with Imperial Guard, since they're the best balanced statline, other than of course Marines themselves. They're cheap, too - and enough things have IG statlines that we can adequately compare points costs and get a decent idea of what exactly Marines do or do not get for free.
A basic Guardsman, as we know, costs 5 points, give or take. Technically, they don't actually, as that would make the Sergeants free in their squads, but I know most people probably don't agree with me in thinking of it that way...either way, let's just assume that 5 points is a fair cost for 3/3/3/3/1/3/1/7/5+ and a Lasgun.
Well, Marines have a point better in nearly all those stats barring Save, so that's a total of 6 stat upgrades. If we price these at a point apiece, which is probably a little cheap, our Marine is up to 11 points...not bad, huh? So, what about equipment? Well, the Marine has a Bolt Pistol, a Bolter, Frags, Kraks - and this is compared to a Lasgun and Frags - so it's going to be at LEAST 3 points worth of gear. More accurately, a Bolt Pistol is 2 points for a guardsman who has the option, a Bolter commonly 3 points, and Kraks manage to squeeze in at one each - so Marines underpay, at best.
What else? Marines start off with Combat Squads, Combat Tactics and ATSKNF, unless from some variant Codex, but it's a fairer comparison if we only do it in relation to the most common tactical Marines, supposedly the epitome of Marine-hood.
These Marines are 16 points each. We had one at 14 points, in Flak Armour, and without those rules. Power Armour, for those GEQs who have the option, costs 8 points.
Since those rules are obviously worth more than a single point apiece (how much would Dark Eldar pay for ATSKHF? How much would Fire Dragons or Orks pay for Combat Squads?!) we know already that the cost is hugely disproportional.
So, no, to answer the original question.
Marines don't actually pay for everything they have. They'd still underpay for the quality difference between them and IG if they were 22 points each.
Let's get this straight - I play Marines too. But let's cut the crap and fanboi whining when Marines don't get everything available to Xenos, huh? Marines get shitloads.