False advertising

I have been on the Leroy Merlin to purchace a few items and I noticed that the pricing on their website is inconsistant, the product will be shown at a different (lower price) then when you click on it the orice goes up, 2 examples are Good Wood fire logs, they show at R29.00 for a pack but when you add them to your trolly it goes to R32,90…. And also Briquettes Master BBQ show as R19 for 2kg but when you add to trolley it goes to R21.90, why is that….why show us the incorrect price to begin with??