I use Vodafone simple which is a sim only bill pay package. Basic pack is €20 for all Vodafone to Vodafone calls and texts included, then 100 mins and 100 texts to other networks. Bill usually runs in around €25 as I might text UK no or go over a little on mins or texts.
You also get 600 webtexts which I tend to use if at home and laptop handy.