Kiwi is NOT transparent in costs - hidden fees: Kiwi does a terrible job of integrating potential cost increases up front. Like sure it'll show you the lowest cost flight up front, but backed behind that are SO many hidden fees that they do not warn you of. Not to mention their documents and emails are not user friendly. Again, not transparent in warnings and reminders. For example, I booked a flight that is typically just 3 hours direct. Kiwi booked two direct flights to my destination and one flight back. Entire thing = $143 - fine sounds reasonable. Come to find out, all flights were Frontier Airlines AND you cannot update baggage on their site once the purchase is made. So, I ended paying in total $278 dollars MORE in just CARRY-ON luggage, a high cost fee for EACH of the flights - 3 total. That is MORE than the original flight tag itself. So total for this whole thing I actually spent $421. Ridiculous. Highly do not recommend using them.