The use of stamps was optional: letters could still be sent requiring payment of postage on delivery. Indeed, the post office did not issue any 2-cent value for prepaying drop letters in 1847, and these continued to be handled as they had been. Nevertheless, many Americans took up using stamps; about 3,700,000 of the 5¢ and about 865,000 of the 10¢ were sold, and enough of those have survived to ensure a ready supply for collectors, although the demand is such that a very fine 5¢ sells for around $500 as of 2020, and the 10¢ in very fine condition, face-free stamped cancellation, with four well spaced borders, sells for $1,500 or more in used form. Unused stamps are much scarcer, fetching around $3,000 and $20,000 respectively, if in very fine condition. One can pay as little as 5 to 10 percent of these figures if the stamps are in poor condition.