Here's an example of the way my brain works. Last week I'm flipping through my shiny new Wilderlands of High Fantasy boxed when my eyes alight on one of the town descriptions. I notice that the town has a 3.x style statblock, listing the gp limit on purchases and total assets of the community. (That's not surprising, considering it's a 3.5 product.) For a sandox setting like the Wilderlands, that sort of information is extremely useful.
But then I got to wondering, how useful are those 3.5 price limits when using the Wilderlands for Castles & Crusades or OD&D or whatever? Or to put it another way, does 1gp have the same buying power across various editions? I vaguely knew that armor gets more expensive across various iterations of D&D, but does other stuff become pricier as well?
Not being an economist by an means nor a master of subtlety, I tried to use a brute force approach to help me answer these questions. The first thing I did was look up the OD&D price list. Then I looked up the costs of comparable items in every other edition of D&D that I own. Here's the raw data, including the starting money ranges for the original three classes.
To better understand the trends of prices across editions, I decided I needed to examine a test case across editions. Enter Morgan Ironwolf. In step 11 of the character creation example in Moldvay Basic (page B13), Morgan Ironwolf's player spends 110 gp as follows:
chainmail armor (40 gp)
shield (10 gp)
sword (10 gp)
shortbow (25 gp)
quiver with 20 arrows (5 gp)
silver-tiped arrow (5 gp)
50' rope (1 gp)
10' pole (1 gp)
12 iron spikes (1 gp)
6 torches (1 gp)
1 week's standard rations (5 gp)
large sack (2 gp)
quart of wine (1 gp)
wine skin (1 gp)
That's 108 out of 110 gp spent, with 2 gold pieces left in petty cash. Morgan started out with an average amount of gold and got a pretty sweet array of equipment. The only glaring omission is a backpack. Which would you rather have if confronted by a wight, a silver arrow or camping equipment?
Anyway, here's a breakdown of how much Morgan would spend under other editions of D&D, with notes on her starting cash situation.
OD&D: Same starting money, but Morgan can afford that backpack now, because her gear costs 105gp.
Holmes Basic: Identical to OD&D
Mentzer Basic: Large sacks are 1 gp cheaper, so Morgan only spends 107gp. Same starting money.
Rules Compendium: Arrows cost 1gp more, so Morgan spends 109gp. Same starting money.
So far not much excitement in this analysis. But let's look at the AD&D line of descent now.
AD&D1: Starting gold for fighters is upped to 50-200, which is good, because Morgan's kit now costs 122.835 gp. Chainmail shoots up from 40 to 75 gp, which is only partially offset by several other items going down in price. Several items that previously cost 1 gp are now priced in silver and copper pieces, the biggest price cut being for ten foot poles, which now costs 1 cp.
AD&D2: Starting gold still 50-200 gp. Silver arrows, 10' poles, and wine seem to have disappeared off the list. The lack of the two former can be taken as another symptom of 2nd edition walking away from hardcore dungeoneering, while the omission of wine strikes me as some sort of joint BADD/MADD plot. Even without these three items, the cost of being Morgan Ironwolf has gone up to 132.85 gp.
3e: Starting gold goes up by a d4, to 60-240gp. Which is good, because a suit of chainmail has doubled in price to 150gp! Morgan's equipment now costs 222.76 gp, requiring a maximum or near-maximum roll to start play with the gear that was easily affordable with average rolls in earlier editions. Quivers and sacks are nowhere to be found.
3.5: Pretty much the same story as 3e, except the total cost is a trifle higher, at 223.06 gp.
I should point out that if go with a chain shirt instead of a whole suit of chain, the 3e and 3.5 versions of Morgan can save some dough. But I think the fair comparison here is a suit of chainmail. Gary makes it explicit in 1st edition that his AC 5 armor is meant to be a whole suit. Until 3e added the chainshirt I think everyone was pretty much on the same page in that regards, except for usual trends in the art to abbreviate the armor.
Now I'll compare a few items that don't count as D&D for some people, but are A-Okay in my book.
Arneson's First Fantasy Campaign: Lack of starting gold and prices for key dungeoneering equipment make a direct comparison impossible, but most of the prices are cheaper than Gary's original list.
Arduin Grimoire: I'll be damned if I can find starting gold for this one. Hargrave gives a dice range for most of his prices. A sword costs 8-20gp, for example. (That's supposed to be 4d4+4, I guess.) I can't find wine, silver arrows, or quivers in volume I of the Grimoire, but everything else would cost between 91.1 and 194.42 gp.
Encounter Critical: Missing some dungeoneering items. The starting gold range for a Warrior of 100 to 800 makes a suit of chain (810 GC) completely out of reach.
HackMaster: Starting gold is all over the map. You can turn in Build Points for 25gp each, but bad die rolls can start you owing money. One time I rolled up this bard with no equipment and over 900 gps in unpaid family debts. Most of the prices for equipment map to the 2nd edition AD&D list, except that armor is very pricey. A suit of chain is 350 gp, way out of reach of the average character. Morgan's stuff would cost 430.27 gp. No ten foot pole!
Castles & Crusades: Generally follows the 2nd edition trend in terms of prices. Starting gold for fighters is 30 to 240gp, getting away from the flatter curve of 5 or 6 dice. My C&C PHB has no silver arrow or iron spikes listed. Buying everything else on Morgan's shopping list would cost 221.96 gp. The C&C Collector's Boxed Set has a slightly different set of prices that also omits quivers and wineskins, with a total cost of 204.96 gp.
Armor seems to be single biggest issue in this test case. How expensive should armor be? Should an average first level fighter be able to begin play in a suit of chain? What does it say about your campaign if nearly every Veteran sports a suit of chain, with some wearing plate? What would it say about your setting if the typical first level fighter wore leather or no armor?
I'm not advocating a right or wrong answer here, but for me personally I think I want starting PCs in chainmail, if that's what they want. I like the idea of handing a newbie a lawful fighter with a sword, a shield, and some chain and saying "Here you go. Basically, you're playing a knight in King Arthur's court. Go do some good deeds or something."