I recommend the An Post Registered option as it provides tracking, proof of postage, and next-day delivery.
Standard postage with An Post is the other option offered although it doesn't provide tracking information. I am not responsible for any lost post.

An Post Standard delivery costs:

Ireland: €3.80
UK & EU: €7 - €8
International: €10

An Post Registered delivery costs:
Ireland: €9.20
UK & EU: €12 - €13
International: €18

Thank you for purchasing at chloetempestini’s website!