in a similar idea (Triskter l Identity theft) i explained how i would set the cost (in this case drop the playing cost of the creature)
they had it as a play 6
![Darkness :darkness](https://elementscommunity.org/forum/Smileys/solosmileys/../../../images/Misc/darkness18x18.png)
and steal an ability so i stated that the creature by itself (2l3) would only cost about as much as a horned toad (3l3) so it would cost 2
![Darkness :darkness](https://elementscommunity.org/forum/Smileys/solosmileys/../../../images/Misc/darkness18x18.png)
then the steal ability 3
![Darkness :darkness](https://elementscommunity.org/forum/Smileys/solosmileys/../../../images/Misc/darkness18x18.png)
making the full card worth 5
![Darkness :darkness](https://elementscommunity.org/forum/Smileys/solosmileys/../../../images/Misc/darkness18x18.png)
applying the same
this creature is just barely weaker than the toad, and should also be 2
![Darkness :darkness](https://elementscommunity.org/forum/Smileys/solosmileys/../../../images/Misc/darkness18x18.png)
now if you have to pay
![Darkness :darkness](https://elementscommunity.org/forum/Smileys/solosmileys/../../../images/Misc/darkness18x18.png)
for the steal, the cost shouldn't be added to both the ability and creature, so it only should be 2
![Darkness :darkness](https://elementscommunity.org/forum/Smileys/solosmileys/../../../images/Misc/darkness18x18.png)
with an ability cost of 3
![Darkness :darkness](https://elementscommunity.org/forum/Smileys/solosmileys/../../../images/Misc/darkness18x18.png)
or 5
![Darkness :darkness](https://elementscommunity.org/forum/Smileys/solosmileys/../../../images/Misc/darkness18x18.png)
with no ability cost