This could be anyone who has come up with the money idea.
1. NDA- They could have staged this for two major purposes to upset the confidence vote and show that if they loose then people from other parties have been bought. Also, if they win they can say in spite of money being offered they won. Also why does a party always comes with alligation when in all probability it is loosing the noconfidence motion. 2. UPA- They have a tainted history related to monitery offers. Also their claims earlier of some MPs abstaining. 3. UNPA- They might come up with the plan as well. They could this way gain in both ways, they knew if offered to some perticular MP, he would create the uproar which means people would either think it is done by UPA or staged by BJP, anyway both would loose credibity but not them.