where is your country
This is the answer for you,maybe you live in one of the country listed on the website that Ailmand have mentioned,try checking the website and look for your country if its listed,if it is then sorry you cant unless you bypass the restriction using VPNs.
Please read first. OP clearly mentioned where he lives.
I live in Dublin and wonder if anyone can help me get hold of $20-$50 worth of BTC?
If you still have troubles, try doing trade on this forum perhaps. Use the Currency Exchange sections on Marketplace and use an escrow to make sure you don't get scammed.