Hi
i had a shop on ebay until recently. Its all quite easy once you get the hang of it. A good program that you should use is Ebay turbolister, its a program that allows you to create listings very quickly instead of the normal 2-3 minutes then you can upload them all at the one time. I recommend setting up a paypal account and getting a deposit if someone is collecting in person or payment in full if posting. Make sure all the items are trackable that you post as some buyeres will try and rip you off by claiming that they never recieved the item. Fastway are good couriers that are much cheaper then anpost too. A shop in ebay costs about €20 per month plus any listing fees that you may have.
Hope this helps