Digital Minimum Dealer Price £0.40p : Only tracks with a minimum PPD of 40 pence or more shall be eligible for the Official Singles Chart. In the event that a record company has an alternative business model
for the sale of downloads (i.e., one not based on a published dealer price), the price charged to the online digital retailer should not be less than 32 pence per track. OCC will monitor sales to ensure they are
‘genuine sales’. Where OCC judges sales not to be genuine, they may be excluded from the chart at OCC’s absolute discretion.

But then, Joe’s website (eggs factory winner) lists Amazon as a place to buy his single to win… odd-Tastic!