Rule of thumb:

From Fallen London Wiki

The Rat Market prices have 3 stages, progressively decreasing as more items are sold. Below are outlined the prices and amounts these prices will last, for all three tiers and a special case:

  • T5
    • 16.5 <style data-mw-deduplicate="TemplateStyles:r1245547">html[data-flw-theme="dark"] .mw-parser-output .flw-echo{filter:invert(70%)sepia(4%)saturate(1224%)hue-rotate(1deg)brightness(102%)contrast(89%)}html[data-flw-theme="light"] .mw-parser-output .flw-echo{filter:invert(3%)sepia(5%)saturate(6260%)hue-rotate(351deg)brightness(96%)contrast(99%)}.mw-parser-output .flw-echo{vertical-align:-8%;margin:0 -6px}</style><a href="/wiki/Penny" title="Penny"><img alt="E" src="/w/images/6/68/Icon-echo-black.svg" width="23" height="15" class="flw-echo" /></a> (First ~52 items)
    • 14 <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1245547"/><a href="/wiki/Penny" title="Penny"><img alt="E" src="/w/images/6/68/Icon-echo-black.svg" width="23" height="15" class="flw-echo" /></a> (Next ~92 items)
    • 12.5 <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1245547"/><a href="/wiki/Penny" title="Penny"><img alt="E" src="/w/images/6/68/Icon-echo-black.svg" width="23" height="15" class="flw-echo" /></a> (Any subsequent items)
  • T6
    • 82.5 <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1245547"/><a href="/wiki/Penny" title="Penny"><img alt="E" src="/w/images/6/68/Icon-echo-black.svg" width="23" height="15" class="flw-echo" /></a> (First ~10 items)
    • 70 <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1245547"/><a href="/wiki/Penny" title="Penny"><img alt="E" src="/w/images/6/68/Icon-echo-black.svg" width="23" height="15" class="flw-echo" /></a> (Next ~18 items)
    • 62.5 <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1245547"/><a href="/wiki/Penny" title="Penny"><img alt="E" src="/w/images/6/68/Icon-echo-black.svg" width="23" height="15" class="flw-echo" /></a> (Any subsequent items)
  • T7
    • 412.5 <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1245547"/><a href="/wiki/Penny" title="Penny"><img alt="E" src="/w/images/6/68/Icon-echo-black.svg" width="23" height="15" class="flw-echo" /></a> (First ~2 items)
    • 350 <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1245547"/><a href="/wiki/Penny" title="Penny"><img alt="E" src="/w/images/6/68/Icon-echo-black.svg" width="23" height="15" class="flw-echo" /></a> (Next ~3.6 items)
    • 312.5 <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1245547"/><a href="/wiki/Penny" title="Penny"><img alt="E" src="/w/images/6/68/Icon-echo-black.svg" width="23" height="15" class="flw-echo" /></a> (Any subsequent items)
  • Mate-Pairs
    • 66 <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1245547"/><a href="/wiki/Penny" title="Penny"><img alt="E" src="/w/images/6/68/Icon-echo-black.svg" width="23" height="15" class="flw-echo" /></a> (First ~13 items)
    • 56 <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1245547"/><a href="/wiki/Penny" title="Penny"><img alt="E" src="/w/images/6/68/Icon-echo-black.svg" width="23" height="15" class="flw-echo" /></a> (Next ~23 items)
    • 50 <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1245547"/><a href="/wiki/Penny" title="Penny"><img alt="E" src="/w/images/6/68/Icon-echo-black.svg" width="23" height="15" class="flw-echo" /></a> (Any subsequent items)

These results are replicable through the use of the above calculators. But for the sake of brevity, I have chosen to outline them here.

Paramount Note: The total bonus of 346 <link rel="mw-deduplicated-inline-style" href="mw-data:TemplateStyles:r1245547"/><a href="/wiki/Penny" title="Penny"><img alt="E" src="/w/images/6/68/Icon-echo-black.svg" width="23" height="15" class="flw-echo" /></a> is gained regardless of the item tier sold. The information presented is approximated for use in the threshold denomination of guides.