US 1st class postage question, need answer fast!

Your math is fault. $10,000 in 42¢ stamps is 23809 stamps (you can’t buy half of a forever stamp.) At 44¢ those stamps would cost $10475.96.

Except that the postage may only go up 1¢; also even if you achieve your desired 4.7596% increase, you do not have an extra $475.96 in your pocket - you have 23809 stamps that you have to stick on envelopes to get your money’s worth.

My bro buys discount stamps. Actually he collects stamps of historic value but while he’s at said meetings, there are people with sheets of postage for sale. I’m guessing they are speculating as the spirit of this implies, reselling them when prices go up.