change_machine.rb

puts "How much $ is due?"
cost = gets.chomp.to_f

puts "How much has been tendered?"
tendered = gets.chomp.to_f

if tendered < cost
	puts "The customer needs to pay you more dough, bro."
else
	change = tendered - cost
	change = change.to_f
end

DOLLAR = 1.00
QUARTER = 0.25
DIME = 0.10
NICKEL = 0.05
PENNY = 0.01

return_dollars = 0
return_quarters = 0
return_quarters
return_dimes = 0
return_nickels = 0
return_pennies = 0

if change > DOLLAR
	return_dollars += 1 until return_dollars = change.floor
	change = change - return_dollars
end
if change > QUARTER
	return_quarters += 1 until change-(return_quarters*QUARTER) < QUARTER 
	change = change - (return_quarters*QUARTER)
end
if change > DIME
	return_dimes += 1 until change-(return_dimes*DIME) < DIME 
	change = change - (return_dimes*DIME)
end
if change > NICKEL
	return_nickels += 1 until change-(return_nickels*NICKEL) < NICKEL 
	change = change - (return_nickels*NICKEL)
end
if change > PENNY
	return_pennies += 1 until change-(return_pennies*PENNY) < PENNY 
	change = change - (return_pennies*PENNY)
end

puts "Return to the customer:"
puts "#{return_dollars} dollars."
puts "#{return_quarters} quarters."
puts "#{return_dimes} dimes."
puts "#{return_nickels} nickels."
puts "#{return_pennies} pennies."

Try to make sure that everything is indented consistently, with 2 spaces. It looks like you are using hard tabs. Make sure that you've got these settings in your Sublime Text settings https://gist.github.com/HeroicEric/77c860d2fe8d7ae0a98f