Board Thread:Bloons Wiki and BTD News/@comment-6834438-20140208143217/@comment-3153244-20140227053411

Theoretically, you can sacrifice $1000,000 of each tower and get the same temple. However, the point is saving money. To get the strongest temple, you only need:
 * $30,000 of Mortars OR Bomb Towers
 * $30,000 of Ice Towers
 * $30,000 of Glue Gunners
 * $30,000 of Monkey Apprentices
 * $30,000 of any combination of other towers.