Land expansions
  Level Costs in island dollars Costs in gold
Expansion (Land) 5/25 10,000 50
  6/25 66,000 390
  7/25 82,000 770
  8/25 200,000 1,200
  9/25 360,000 1,600
  10/25 610,000 2,100
  11/25 900,000 2,100
  12/25 1,300,000 3,200
  13/25 1,800,000 3,900
  14/25 2,400,000 4,500
  15/25 3,100,000 5,200
  16/25 4,200,000 5,900
  17/25 5,400,000 6,700
  18/25 6,900,000 7,500
  19/25 8,800,000 8,400
  20/25 12,000,000 9,300
  21/25 14,000,000 10,000
  22/25 17,000,000 11,000
  23/25 20,000,000 12,000
  24/25 25,000,000 13,000
  25/25 30,000,000 14,000
   
  courtesy of Bailey: Big Farm Wiki : Big Farm Wiki

UPDATED 3/8/2019