Just nipped down to Tesco Express in Westhoughton for my dinner (lunch for non-howfeners). Picked up a 500ml bottle of Pepsi for 21p, checked it with the lad in the shop and he wasn't sure if it was right or not. Scanned at 21p at the self service till, loads left.
EDITED as some people are saying that are getting them at 20p. Plenty of time left on the best before date too.
This Maybe an In-Store Deal Only!