x 1 Document sends = £1.60 (@ £1.60 per Envelope)
x 10 Document sends = £15 (@ £1.50 per Envelope)
x 25 Document sends = £35 (@ £1.40 per Envelope)
x 50 Document sends = £65 (@ £1.30 per Envelope)
x 100 Document sends = £120 (@ £1.20 per Envelope)
x 200 Document sends = £230 (@ £1.15 per Envelope)
