Board Thread:Questions and Answers/@comment-75.159.4.201-20140317211832/@comment-3153244-20140318100458

You can conserve on your Bloonstones - there are no other ways I know of to acquire Bloonstones.

If you maximise your Bloontonium storage by building as many Bloontonium Storage Tanks as your level allows you, you will be able to attack most players without spending Bloonstones.

This is because you only need to use Bloonstones in MvM if you do not have enough Bloontonium for an attack.