Ireland

Default data rate
You pay daily as you use the service, and you only pay for the days you use. Standard rate is €0.99 for a 50MB daily usage allowance, and €1 per MB thereafter (0.1c per KB). If you use less than 0.5MB, you only pay for the pages you use. (See link )

Data feature packs

 * 1Gb per month for €9.99. With this add on:
 * Price per MB after you have used your bundle is €1
 * Unused MBs cannot be carried forward to the next month

SIM sizes
Micro SIM available.

Tethering
Allowed. 5GB for €20, lasts 30 days. Vodafone warns you on its website that "If you do use tethering without an add on, it can be expensive. For example, Perfect Choice Access Plus pay monthly customers will pay 2c per kb for the first 512kb and 2c per MB thereafter – so the first 1MB costs €10.25 and the first 1GB costs €30.71."