Oh god more spreadsheets

Is it better to buy minerals from sell orders, or to make a buy order? Find the answer, using the power of spreadsheets!

What is this I don't even? Well, instead of pasting all the maths here, since I doubt anybody would be interested, I'll tell you how it's used, which is the important part. Nobody is likely interested in that either, but whatever.

1. Once I know the mineral quantities that I need, they go in the 'units needed' row of the top table.

2. For each mineral I check the in-game market for two values:

2a. The per-unit price for the lowest-price sell order which fulfills my mineral requirements. This goes in 'market price' in the second table.

2b. The per-unit price which I would offer if I were to make a buy order, which is usually 0.01 isk above the current highest buy order of significant quantity. This number goes in the 'buy order price' column of the second table.

3. I then go to the 'buy order taxed' column of the second table. This figure is equal to the 'buy order price' column multiplied by 1.0075, which is the tax rate on buy orders (with perfect skills, of course), meaning that I can save money if there are any minerals for sale for less than that number. I check each mineral for cheaper sell orders, and buy them. The quantity purchased goes in the columns in the 'bought' section of the top table, and the 'still need' row and column change to reflect how many minerals I still need.

Usually the 'difference' number being red means I will not need to place a buy order for that mineral, and it being black means I will not buy anything from the market, but there are exceptions.

The screenshot above is for build #14 after I finished step 3. Note that 'bought' entries only appear for those minerals with red in the 'difference' column.

4. Once that is done, I make buy orders for everything that's left, then check back every so often and play the 0.01 isk game until my buy orders are filled. I used to have a rule against playing 0.01 isk games, but I rarely need to change the price more than maybe twice. Not exactly a huge time sink.

• Note: In case you couldn't tell, the 'difference after tax' figure tells me how much I save by making a buy order instead of buying from market. It's not exact, and isn't actually used for anything, but it is nice.
• Note: I'm not actually sure this is the best way to do things, and I am sure the spreadsheet could be cleaned up a lot. I just converted this from an impromptu tool which I had been using until now, and invented the process as I wrote the post.
• Note: The bottom table is arranged perpendicular to the top table, and in a different order, for ease of use.
• Note: The 'still need' column and row are identical. Having the data in both tables just makes things easier.
• Note: I round mineral quantities I buy up a little because my spreadsheet reads very slightly low when calculating minerals. This is periodically corrected -- when all component runs on my build tracker are in progress, I can see how much excessive minerals have built up, and those numbers are put into the 'bought' row of the top table when I start the next run.