Cloudberry Kingdom, Echochrome, Galaga Legions DX, ibb & obb, Katamari Damacy, Noby Noby Boy, Pac-Man Championship Edition DX+, Rock of Ages, Sam & Max: Season 1 & 2 & Tokyo Jungle, PS3 – £6.69
First, purchase $10 PSN credit from Amazon US for £6.69. To purchase digital goods from Amazon US, use your UK Amazon account, and add a US billing address to your account. This address needs to be a valid US address, but nothing will be sent there. Some card issuers may charge a fee.
Then using a US PSN account, activate the credit, and use it to buy all of these off the US Playstation Store for just shy of $10.
If you already own, or are uninterested in any of these titles, there are a bunch of other games at similar prices listed here.