This deal combines 3 different offers on Amazon Pantry -
Buy 4 items get free delivery
Buy 4 items get £3 off
Buy 2 x Mr Muscle Oven Cleaner get £5.00 off (making them free)
To make the most of the offer you want to purchase the items that are £1. An example is shown in the 1st post. You can order more than one of each product rather than 8 different items.
Credit to twinkle for noticing that 2 oven cleaners takes £5 off instead of just the 1 with £2.50 off
UPDATE - oven cleaner currently out of stock. The other two offers still apply.