Question: how many stamps to mail a letter to kenya?
Answer: 3 - one standard forever (letter - $0.50) and two postcard forever (2 x $0.35 = $0.70), but you're still wasting money ($1.20 vs $1.15 required.) 4 - forever post card stamps (value $0.35 in 2018) but again you'll be wasting money.