Another incredibly cheap PSN deal seems to have emerged involving Pay As You Go sim cards, which allow you to convert your mobile credit directly into PSN credit - effectively doubling your money in the process.
Here's how it works.
Step 2: top up £5, £10, £20 or £50 within 30 days and an equal amount of extra credit will be added.
A bit of a fuss, but probably well worth it for a huge amount of credit. Thanks Gooner!