Go to any major component suppliers website and use their parametric search facilities to make your choice and get the devices listed in order of price.
Might be cheapest to get something off ebay, taking whatever you can find even if they're massive overkill for a mere 2W. Then again a discreet design for 2W seems like overkill to me too, instead of some ready to roll chipamp IC with the transistors already in it.
You can get a whole amp board for less than $2 USD delivered world-wide which could be less than postage alone costs to mail anything from an electronics supplier.