It looks as if game rentals are on their way to the PlayStation Store, if an image tweeted to (and verified by) PSNStores is to be believed.
At the time of writing, the store appears to have been updated to remove the rental options, but late yesterday, alongside the $9.99 purchase option for Atlus' excellent puzzle adventure and infidelity simulator Catherine, the PlayStation Store offered 1, 7 and 30 day rental options. The rental options were priced at "free" so PSNStore's Chris K went through a full checkout process to see what happened, and discovered that an option called "Catherine PSNow" had been added to his Services List under Transaction Management. Moreover, the Catherine software was not added to his download list, suggesting that the rental options may well be exclusive to the upcoming PlayStation Now game-streaming service.
Earlier in the week, we saw a mockup screenshot from Gaikai showing some possible prices for PlayStation Now rentals, though there was no indication of the period you would be able to play the game for when you paid your $4.99 or $5.99. Presumably prices will vary according to the games in question -- something like Catherine is only $9.99 in the first place, so for rental to be a cost-effective, attractive option for players it will need to offer a substantial saving over simply buying the game. This is further backed up by the mockup screenshot, which showed Uncharted 3 as costing $4.99 on PlayStation Now, while Far Cry 3 cost $5.99.
A lot of questions still surround PlayStation Now. Will you be able to transfer your save files from the PlayStation Now rental version to the full downloadable version if you decide to purchase it? What will the performance and quality be like on an average home broadband system? When does the damn thing actually launch? GDC is next week; with any luck, we'll get a few more answers then. For now, the service continues to be largely shrouded in mystery, but the information that has leaked out this week gives us a slightly better idea of how the transaction side of it will work.