300 units/per month will cost £0
701 units/per month will cost £31.03 [701 x 0.03/renda + Flat fees £10]
10,001 units/per month will cost £170.01 [10,001 x 0.01/renda + Flat fees £70]
150,000 units/per month will cost £1500
300,000 units/per month will cost £2500