Premium currency hides the real price
Bundles are usually priced so that you cannot buy exactly what you need, leaving a small balance behind. Convert the cost back to New Zealand dollars before deciding whether an offer is good value.
Timers sell convenience, not power
In builders such as Elvenar or Sunrise Village, most spending removes waiting. That is the fairest form of monetisation: patience is a genuine substitute for money.
Competitive advantage is a different question
In competitive strategy servers, spending can translate directly into troop numbers or commander strength. If you intend to stay free, choose an established alliance and a less contested server.
Randomised rewards deserve caution
Packs with random contents can cost far more than a fixed price for the same item. Treat them as entertainment spending with no guaranteed outcome, and set a hard limit before you open the first one.