Just a small rank shop gui (ranks: silver, gold, diamond. If you want feel free to change them..
cmd create rankshop §b>RANK SHOP BY XXWme/CrimsonSky<
cmd add rankshop %gui%[\"type\"] = \"form\"
cmd add rankshop %gui%[\"title\"] = \"§bRank Shop\"
cmd add rankshop %gui%[\"content\"] = \"Click a button to buy the rank!\"
cmd add rankshop %b0%[\"text\"] = \"§7Silver\"
cmd add rankshop %b1%[\"text\"] = \"§6Gold\"
cmd add rankshop %b2%[\"text\"] = \"§bDiamond\"
cmd add rankshop %bs%[] = %b0%
cmd add rankshop %bs%[] = %b1%
cmd add rankshop %bs%[] = %b2%
cmd add rankshop %gui%[\"buttons\"] = %bs%
cmd add rankshop %res% = dialog(%p%, %gui%)
cmd add rankshop if %res% = 0 then goto 40
cmd add rankshop if %res% = 1 then goto 50
cmd add rankshop if %res% = 1 then goto 60
cmd add rankshop exit
cmd insert rankshop 40 %mybal% = playerbalance(%p%)
cmd add rankshop if %mybal% > 3999 then goto 44
cmd add rankshop message %p% §8>> §cNot Enough Money! §8<<
cmd add rankshop exit
cmd add rankshop ascon /takemoney %p% 4000
cmd add rankshop ascon /setgroup %p% Silver
cmd add rankshop message %p% §aPurchase successful!
cmd add rankshop exit
cmd insert rankshop 50 %mybal% = playerbalance(%p%)
cmd add rankshop if %mybal% > 5999 then goto 54
cmd add rankshop message %p% §8>> §cNot enough money!§8 <<
cmd add rankshop exit
cmd add rankshop ascon /takemoney %p% 6000
cmd add rankshop ascon /setgroup %p% Gold
cmd add rankshop message %p% §aPurchase successful!
cmd add rankshop exit
cmd insert rankshop 60 %mybal% = playerbalance(%p%)
cmd add rankshop if %mybal% > 9999 then goto 64
cmd add rankshop message %p% §8>>§c Not enough money! §8<<
cmd add rankshop exit
cmd add rankshop ascon /takemoney %p% 10000
cmd add rankshop ascon /setgroup %p% Diamond
cmd add rankshop message %p% §aPurchase successful!
cmd add rankshop exit
cmd create rankshop §b>RANK SHOP BY XXWme/CrimsonSky<
cmd add rankshop %gui%[\"type\"] = \"form\"
cmd add rankshop %gui%[\"title\"] = \"§bRank Shop\"
cmd add rankshop %gui%[\"content\"] = \"Click a button to buy the rank!\"
cmd add rankshop %b0%[\"text\"] = \"§7Silver\"
cmd add rankshop %b1%[\"text\"] = \"§6Gold\"
cmd add rankshop %b2%[\"text\"] = \"§bDiamond\"
cmd add rankshop %bs%[] = %b0%
cmd add rankshop %bs%[] = %b1%
cmd add rankshop %bs%[] = %b2%
cmd add rankshop %gui%[\"buttons\"] = %bs%
cmd add rankshop %res% = dialog(%p%, %gui%)
cmd add rankshop if %res% = 0 then goto 40
cmd add rankshop if %res% = 1 then goto 50
cmd add rankshop if %res% = 1 then goto 60
cmd add rankshop exit
cmd insert rankshop 40 %mybal% = playerbalance(%p%)
cmd add rankshop if %mybal% > 3999 then goto 44
cmd add rankshop message %p% §8>> §cNot Enough Money! §8<<
cmd add rankshop exit
cmd add rankshop ascon /takemoney %p% 4000
cmd add rankshop ascon /setgroup %p% Silver
cmd add rankshop message %p% §aPurchase successful!
cmd add rankshop exit
cmd insert rankshop 50 %mybal% = playerbalance(%p%)
cmd add rankshop if %mybal% > 5999 then goto 54
cmd add rankshop message %p% §8>> §cNot enough money!§8 <<
cmd add rankshop exit
cmd add rankshop ascon /takemoney %p% 6000
cmd add rankshop ascon /setgroup %p% Gold
cmd add rankshop message %p% §aPurchase successful!
cmd add rankshop exit
cmd insert rankshop 60 %mybal% = playerbalance(%p%)
cmd add rankshop if %mybal% > 9999 then goto 64
cmd add rankshop message %p% §8>>§c Not enough money! §8<<
cmd add rankshop exit
cmd add rankshop ascon /takemoney %p% 10000
cmd add rankshop ascon /setgroup %p% Diamond
cmd add rankshop message %p% §aPurchase successful!
cmd add rankshop exit