# Talk:Grum's Gold Exchange.

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Wouldn't it be more helpful to display the price he pays for items when his stock is at zero, rather than the price for items you can't buy?  —The preceding unsigned comment was added by 205.237.163.193 (talk) on 22:41, November 13, 2016 (UTC).

The data was already there, template just needed fixing to display the buy price. Updated it! -Shaun Dreclintalk 08:17, July 1, 2017 (UTC)

## What is the formula to calculate the value decrease per item sold?

I don't know how to ask this, but how are we supposed to see the formula which is used to calculate the shop's price change when there are more than 0 of an item in the store's stock? I just tested it and for an Emerald Necklace, when at 0 in stock, the price is indeed 997. But the values after that are: 969, 940, 912, 883 (for 4 items in stock, 883 being the amount of gp you would get for selling the 5th necklace). This means that the average decrease for the Emerald Neckalace per item sold is 28.5 gp. When taking into consideration General store's sell price, I can't seem to find the formula to give the exact amount decreased per item sold. I don't know if the Low alchemy price or High alchemy price is taken into consideration.

I would also like to know if the amount of gp decrease per item is constant or is variable with the necklace's price?

Help? MaxStein (talk) 12:00, 24 May 2019 (UTC)

The formula for the buy/sell values of an item is ${\displaystyle {\frac {{\text{item value}}*({\text{∆stock}}*A+B)}{1000}}}$
Where ${\displaystyle A}$ is always the same for a store, but ${\displaystyle B}$ changes based on whether you're buying or selling. Each store has its own ${\displaystyle A}$ and ${\displaystyle B}$ values. This particular store has an ${\displaystyle A}$ value of 20, and a ${\displaystyle B}$ value of 1000 or 700, depending on if you're buying or selling.
There are a handful of caps in place, but the only one worth mentioning is that you'll always get at least 10% of an item's value when selling it to a shop. (Worth mentioning that high alch yields 60% of an item's value, if you just want to quickly calculate it.)
Helped.-Towelcat (talk) 12:09, 24 May 2019 (UTC)
Ok, that seemed to help, but you didn't tell me about Δstock. Got everything else ready to calcultate, but that stock is messing the results. MaxStein (talk) 15:57, 26 May 2019 (UTC)
Δstock just means "change in stock", i.e. the difference between default stock and current stock. As an example, this shop has a default stock of 0 for each item, so if the current stock of an item is 5, Δstock would be ${\displaystyle 0-5=-5}$. From there, the effective multiplier when selling an additional item would be ${\displaystyle {\frac {-5*20+700}{1000}}=0.6}$.-Towelcat (talk) 16:23, 26 May 2019 (UTC)
Well, now everything makes sense and the equations are working properly. Didn't calculate item's value properly so the results were all over the place. Now it's all good.
I would also want to know what is the price cap on buying items. From High Level Alchemy's Gold necklace example, the lowest price you can buy items from a shop is 10% of that item's value, price which is attained at 30+ items in stock. Is that correct? Because my calculations show that at 30 items on shop's stock the price is 40% of item value. Is that the real cap? MaxStein (talk) 10:24, 27 May 2019 (UTC)
The example on that page was for selling to the shop, where it would indeed reach 10% after 30 items. ${\displaystyle {\frac {-30*20+700}{1000}}=0.1}$
• When selling to a store, the price will be between 10% and 150% of the item value.
• When buying from a store, it takes the maximum of 1, 10% item value, item_value * (B-1000)/1000, or item_value * (∆stock*A + B) / 1000
-Towelcat (talk) 15:08, 27 May 2019 (UTC)
I'm sorry, I didn't quite get that. An actual example would be perfect, but here is what I understood: When buying from a shop - depending on the stock number - the minimum price you can buy that item for is the maximum value of one of the three: 10% of the item's value OR item's value * (B-1000)/1000 (which is always 0, because B = 1000 since I'm buying) OR item's value * (∆stock*A + B) / 1000 which seems to be the formula used to calculate the actual decrease in buying price when the stock is increasing.
It might be that the minimum buy price is not at 30 items in stock and that it is actually variable with the item's value.MaxStein (talk) 11:21, 1 June 2019 (UTC)
Resetting indent.
It depends on the A and B values, not the item's base value.
In order to reach that 10% value when buying, you'll need to overstock 45 items first. ${\displaystyle {\frac {-45*20+1000}{1000}}=0.1}$
When selling, it only requires 30. ${\displaystyle {\frac {-30*20+700}{1000}}=0.1}$
(I may have misunderstood your question. Lemme know if you still need help.)-Towelcat (talk) 13:02, 1 June 2019 (UTC)
Yey! That's what I wanted to know. So the formula for prices is the one you gave me above, with A, B and ∆stock, and the minimum buying price is achieved at 45+ items in the shop's stock. That's awesome. I can now truly Thank you! MaxStein (talk) 16:15, 1 June 2019 (UTC)
One more thing: Where did you get the store's specific A and B values? Is there a page where there are all the shop's values? Didn't manage to find it. If you don't mind pointing the right page, please.MaxStein (talk) 20:31, 24 December 2019 (UTC)
Edit: I guess I can calculate A and B of a store by checking the buy/sell price of two different items. Seems rather complicated, but I guess it's not. MaxStein (talk) 22:49, 4 January 2020 (UTC)

## Release date

See this map from 2001-04-06 showing this shop absent with the initial Asgarnia update. Obviously, jewellery didn't exist yet. It's present in config18 (2001-05-08), which is the jewellery update. -- Xell Khaar (talk) 10:32, 8 March 2020 (UTC)