"Price ratio" is the unmodified number for calculating the cost of the next thing in a series (buildings, space items, time upgrades, etc). You'll find it listed on the Buildings and Space pages (and probably many other places).
To use this, you multiply the current cost * the price ratio and that's what the next building will cost.
For example:
The price ratio is modified by a bunch of things; here's a few common ones, but there are many more:
| Upgrade | Reduction | Notes |
|---|---|---|
| Engineering | -0.01 | Affects all structures |
| Golden Ratio | -(1 + Math.sqrt(5)) / 200 ~= 0.01618 | Affects all structures |
| Divine Proportion | -16 / 900 ~= -0.0177777778 | Affects all structures |
| Vitruvian Feline | -0.02 | Affects all structures |
| Renaissance | -0.0225 | Affects all structures |
| Ironwood Huts | -0.50 | Affects only Huts |
| Concrete Huts | -0.30 | Affects only Huts |
| Unobtainium Huts | -0.25 | Affects only Huts |
| Eludium Huts | -0.10 | Affects only Huts |
This changes the calculation to something like this: current cost * (price ratio - metaphysics modifiers - building modifiers).
So in the example above, if you had all the metaphysics upgrades, this is what the calculation would look like:
Okay, okay, we all know why we're here. This is the answer according to WolframAlpha.
But here's the table to save you some time. This assumes you have all the metaphysics upgrades.
| Chronosphere | Unobtainium | Total cost |
|---|---|---|
| 1 | 2500 | 2500 |
| 2 | 2909 | 5409 |
| 3 | 3385 | 8793 |
| 4 | 3938 | 12.73K |
| 5 | 4582 | 17.31K |
| 6 | 5332 | 22.64K |
| 7 | 6203 | 28.84K |
| 8 | 7218 | 36.06K |
| 9 | 8398 | 44.46K |
| 10 | 9772 | 54.23K |
| 11 | 11.37K | 65.60K |
| 12 | 13.22K | 78.82K |
| 13 | 15.39K | 94.21K |
| 14 | 17.91K | 112.12K |
| 15 | 20.83K | 132.95K |
| 16 | 24.24K | 157.19K |
| 17 | 28.21K | 185.40K |
| 18 | 32.82K | 218.22K |
| 19 | 38.19K | 256.41K |
| 20 | 44.44K | 300.85K |
| 21 | 51.71K | 352.56K |
| 22 | 60.16K | 412.72K |
| 23 | 70.00K | 482.72K |
| 24 | 81.45K | 564.17K |
| 25 | 94.77K | 658.94K |
| 26 | 110.27K | 769.21K |
| 27 | 128.31K | 897.52K |
| 28 | 149.29K | 1.04M |
| 29 | 173.71K | 1.22M |
| 30 | 202.12K | 1.42M |
| 31 | 235.18K | 1.65M |
| 32 | 273.64K | 1.93M |
| 33 | 318.39K | 2.24M |
| 34 | 370.46K | 2.62M |
| 35 | 431.05K | 3.05M |
| 36 | 501.54K | 3.55M |
| 37 | 583.57K | 4.13M |
| 38 | 679.00K | 4.81M |
| 39 | 790.05K | 5.60M |
| 40 | 919.26K | 6.52M |
| 41 | 1.06M | 7.58M |
| 42 | 1.24M | 8.82M |
| 43 | 1.44M | 10.26M |
| 44 | 1.68M | 11.94M |
| 45 | 1.96M | 13.90M |
| 46 | 2.28M | 16.18M |
| 47 | 2.65M | 18.83M |
| 48 | 3.08M | 21.91M |
| 49 | 3.59M | 25.50M |
| 50 | 4.18M | 29.68M |
| 51 | 4.86M | 34.54M |
| 52 | 5.66M | 40.20M |
| 53 | 6.58M | 46.78M |
| 54 | 7.66M | 54.44M |
| 55 | 8.91M | 63.35M |
| 56 | 10.37M | 73.72M |
| 57 | 12.07M | 85.79M |
| 58 | 14.04M | 99.83M |
| 59 | 16.34M | 116.17M |
| 60 | 19.01M | 135.18M |
| 61 | 22.12M | 157.30M |
| 62 | 25.74M | 183.04M |
| 63 | 29.95M | 212.99M |
| 64 | 34.85M | 247.84M |
| 65 | 40.54M | 288.38M |
| 66 | 47.18M | 335.56M |
| 67 | 54.89M | 390.45M |
| 68 | 63.87M | 454.32M |
| 69 | 74.32M | 528.64M |
| 70 | 86.47M | 615.11M |
| 71 | 100.61M | 715.72M |
| 72 | 117.07M | 832.79M |
| 73 | 136.22M | 969.01M |
| 74 | 158.49M | 1.12G |
| 75 | 184.42M | 1.31G |
| 76 | 214.58M | 1.52G |
| 77 | 249.67M | 1.77G |
| 78 | 290.50M | 2.06G |
| 79 | 338.01M | 2.40G |
| 80 | 393.29M | 2.79G |
| 81 | 457.61M | 3.25G |
| 82 | 532.45M | 3.78G |
| 83 | 619.53M | 4.40G |
| 84 | 720.85M | 5.12G |
| 85 | 838.74M | 5.96G |
| 86 | 975.91M | 6.94G |
| 87 | 1.13G | 8.07G |
| 88 | 1.32G | 9.39G |
| 89 | 1.53G | 10.92G |
| 90 | 1.78G | 12.70G |
| 91 | 2.08G | 14.78G |
| 92 | 2.42G | 17.20G |
| 93 | 2.81G | 20.01G |
| 94 | 3.27G | 23.28G |
| 95 | 3.81G | 27.09G |
| 96 | 4.43G | 31.52G |
| 97 | 5.16G | 36.68G |
| 98 | 6.00G | 42.68G |
| 99 | 6.99G | 49.67G |
| 100 | 8.13G | 57.80G |