Nutty Gearbest pricing on the Zanflare F1

I noticed that the Zanflare F1 was on sale at Gearbest via a link on Youtube and at the very keen price of £15.91. It’s not a torch I need but at that price, it was a must buy. I put it in my shopping basket but on payment, I was told that this not was not available in my region at that price. I, therefore, cancelled the purchase. I have just been pootling through Facebook and the Zanflare turns up in a pop-up add for £19.02. I go through the link for that ad, of course, that figure has now changed to £23.86. How can they be so inconsistent? I’m in the UK so postal prices should not be much different from China to the UK than they are from the USA.