Trying to book a holiday and each time I press 'book' on either Tui or First Choice, both add hundreds extra at checkout with the pop up 'this holiday has increased by £954 while you have been on the site'. I've tried 4 different devices, using data rather than wifi, still the same. Tried different dates/holidays and as I book the pop ups have been £752, £864 and now £952. So frustrating. We have given up. Anyone else managed to avoid this? I've been trying a period of over 3 weeks with the same result. I can't believe every flight changes every time I attempt to book, surely?? Feel like Tui and FC are taking us as chumps! Grrrrr