MTGNexus

Temple of Bloodletting
Land
{3}, {T}: Add C. Each opponent loses 1 life. You gain life equal to the life lost this way.
Whether it was built for worship or for medicine, it wrought only disease and death. Edit 1: Updated the activated ability's generic mana cost to reflect feedback (from {2} to {3}).

Being unable to add mana without the effect definitely means you can cheapen it. However, when you look at similar effects and consider that you are getting a refund on the mana spent to activate this is way undercosted. Orzhova, the Church of Deals, Shivan Gorge. I think should work as a cost. The difference of 1 mana when that low is fairly significant.

Agreed, the cost of the activated ability is slightly to low for the effect.