Just back from Tanzania. At Kilimanjaro airport, all US citizens were getting charged $100 for visas as the immigration officials there claimed the Visa price just got hiked a few days before. I'd advise all folks travelling there to double check before they leave otherwise be prepared to pay. We thought it was a scam at first, but a UN official in line was charged as well despite her putting up objections. I switched pasports quickly and presented my UK one (dual national!). Luckily UK citizens are still $50. What a place!!