ayne31 wrote:Then i got screwed again for 15 points as the complete spell cost also only 15 - I wil have to buy the complete acid2 to get the credit upgrade
Or you can use a higher credit. Remember, your Credit Value (right col) has to be equal to or GREATER than your Casting cost (left col). It's ok to go over on credits, in fact, you'll get a difficualty bonus for doing it, which means your sucess rate will go up (to a maximum of 95%)!
Or, just look for a different unrelated spell that gives that credit (like Cold 2) and get that. Problem solved. You'll need Cold or Rot eventually anyway...