Best price I could find for Viva Pinata is just £24.99 at Argos. This item is not available for home delivery (which costs anyway) but can be picked up in-store, subject to availability.
Aside from Argos, the best price around seems to be Game, where you can get it for £29.99 (delivered + quidco too), so you'd still be saving at least a few quid if you can get it from Argos.
I have been checking daily to see if this game has come into stock at my local Argos for the past fortnight and last night (finally!) it appeared as stock available so I reserved it and collected it today from Wolverhampton store nearish to where I work.
Store availability is very patchy though and it seems to go out of stock very quickly so make sure to reserve and collect if you want it and get the opportunity. It's still available at some stores so you might get lucky. Failing that, a bit of patience and you might see it get restocked soon. Or pick it up from Game for a few quid more.
Product code is 568/2667 at Argos.