Item Price Predictions

• Intro: Fluctuating Item Prices and Item Stocks in Stores
• Lanfear's Predictions for Smithed Items

Introduction: Fluctuating Item Prices and Item Stocks in Stores

Over the past couple of days, I (Visolela) did some more calculations with smithed item prices and what we know and don't know. I'm not done yet, but it turns out that the General Stores not only buy from players at lower prices than specialty stores do (like Lanfear says), but they also mark up the items they sell. The markup is usually 25%. So if a bronze plate mail costs 160 gp to buy from Horvik the Armorer, it would cost 203 gp if you bought it from the general store (assuming it only had one to sell). The other thing that goes on at all stores is that they all have a default amount of some item to sell (like how on a quiet day, Aubury has a stock of 50 of most types of runes to sell). But if you have 200 air runes to sell Aubury, and you drive his stock up, he will pay you less and less per rune until you're 'selling' them for 0 gp. Also, if you drove up his stock high enough, he'd start selling his runes at 1 gp a piece, even though he normally sells them for 4 or 5 gp. I don't know how that's all figured, but it's something to keep in mind when buying or selling.

When I smith steel (I'm just starting), I usually end up smithing about 15 to 20 steel medium helmets. The first one I sell to Peska the Helmet merchant in the Barbarian Village for 180 gp. The next one is something like 175 gp. When I get to the last one, I end up selling it for under 140 gp. The other thing that goes one is that Peska's selling price for the helmet goes down. From the time just before I start selling him mine, he's selling steel helmets for 300 gp. When I'm done driving up his stock, he's selling them for around 250 or 260 gp.

The final thing you need to know about buying and selling from NPC merchants is that over time, their stocks normalize to whatever the default is. Again, if I'm selling to Peska, and I have all the time in the world, I could actually get 180 gp for each helmet. Over the period of a couple of minutes, if he's got more than 5 steel helmets, one of this stock will disappear, and the price he will buy it from me increases. So if I sold him one steel helmet for 180 gp and he had 6 helmets in stock, if I just wait a couple of minutes, he'll have 5 again, and I can sell another one to him for 180 gp. All merchants work this way. If there were a general store that had no buying customers, only customers who sold stuff to them, if you waited long enough and no one sold anything to them, you'd eventually find that they'd just have the few pots, jugs, buckets, pickaxes, hammers, tinderboxes, chisels and so on that every general store has. Merchants will also just spontaneously generate items in their stock if their stock is under default values. This also happens at about the same pace.

Also, if the item is valuable, sometimes it will take longer to regenerate in stock. This is why it can take so long for someone who's got the cash to get adamantite legs or skirts. Those items seem to take a long time to regenerate in the stock of Horvik, or the skirt merchant in Al Kharid.

Item prices seem to be based on a formula like this:

Store item selling price = Item base price * store selling modifier * stock modifier

and

Store item buying (from players) price = Item base price * store buying modifier * stock modifier * player selling modifier

Item base price is what Lanfear is predicting below, and what we present as 'buy' price in our tables on the smithing and items pages.
Store selling modifier is either 1 in case of a specialty shop or 1 1/4 in case of a general store
Store buying modifier is either 1 in case of a specialty shop or 2/3 in case of a general store
Stock modifier is a fudge factor based on whether the store is overstock or understock according to their default stock (greater than 1 for understock, less than 1 for overstock, 1 if store has default amount of stock)
Player selling modifier is 0.6. (speciality shops generally buy at 60% of the value they sell for).

So watch out when you take note of costs and when you buy and sell from NPC merchants. You may find a price that's a lot lower or a lot higher than you were expecting. These kinds of adjustments are why this happens.

Lanfear's Predictions for Smithed Items

Lanfear submitted some very useful information. It differs enough from some of our observed values that we thought there should be a separate page for reference. If we find that the information here is more accurate, we'll redo the smithing pages to incorporate the data.

Still, there's a really high level of correspondence here with the observed facts, so this information definitely belongs on RUNESCAPE Tips.

Thanks, Lanfear!

Here's how Lanfear figured the information below:

NOTE: This was made some time ago, so the black items doesn't compute with the others price system.

Medium helm 15% (of the ore's plate cost)
Large helm 27.5% (of the ore's plate cost)
Mail 37.5% (of the ore's plate cost)
Legs 50% (of the ore's plate cost)
Long Sword 25% (of the ore's plate cost)
Short Sword 16.25% (of the ore's plate cost)
Dagger 6.25% (of the ore's plate cost)
Battle Axe 32.5% (of the ore's plate cost)
Axe (hatchet) 10% (of the ore's plate cost)
Scimitar 20% (of the ore's plate cost)
Square Shield 30% (of the ore's plate cost)
Kite Shield 42.5% (of the ore's plate cost)

General store buys for 40% of the item's cost
Specialized store buys for 60% of the item's cost

We're presenting the information he submitted in tabular form. We hope it's more utilitarian this way. Below is a list of shops' selling prices for items. Some of this information is verifiable. Some of it we don't know, because, for instance, Horvik the Armorer doesn't sell Adamantite Plate Mail yet, and no one can make it yet. Still the predictions look almost dead on:

Highlighted in RED are Lanfear's recent updates.

Please send me suggestions and updates to my e-mail: runescape@tip.it.
Edited by Visolela.