A lot of actor fees are buy-outs, they get one fee and that's it. Only the big name stars can command a fee each time the ad is shown. The same goes for voice-overs - a well known name with a recognisable voice will get more than a jobbing voice-over actor.
I would say the production costs of animated commercials is far more than live-action (though it depends on the scale of live-action filming). For one thing it takes longer to make an animated ad. But most of the cost of the campaign goes on the ideas and the advertising space itself, the production costs are only a part of it.
Also, a lot of the animated and puppeteered adverts still use a live-action setting that has to be filmed, and they still employ actors to provide the voice of the animated character (think of the Tetley Tea Folk and Compare the Market ads).