Sandhill is considering introducing a water filtration device for its one-litre water bottles. Market research indicates that 1,000,000 units can be sold if the price is no more than $4. If Sandhill decides to produce the filters, it will need to invest $2,100,000 in new production equipment. Sandhill requires a minimum rate of return of 20% on all investments. Determine the target cost per unit for the filter. (Round answer to 2 decimal places, e.g. 15.25.)