One of the few requirements of attendance at an SCA event is that you attempt to wear pre-16th century clothing. In the SCA some use the term Garb to differentiate all forms of medieval clothing from modern clothing.
Medieval clothing takes a variety of forms according to period and culture.
If you're a newbie you can arrange for someone, such as the hospitaller or gold key to lend you garb for your first few events until you have your own garb. It could be something as simple a t-tunic or as elaborate as an Elizabethan farthingale.
If you can't sew, you can always find plenty of people to help you. If you don't want to sew, you can always pay someone to make it for you, or offer whatever trade or skill you have in exchange for garb.
- Links, links and more links - http://moas.atlantia.sca.org/topics/clot.htm
- Irish clothing from legendary to Tudor - http://www.reconstructinghistory.com/irish/
- Scots, including the truth about the great-kilt - http://reconstructinghistory.com/scottish/
- Japanese - http://www.reconstructinghistory.com/japanese/
- Lots of stuff on middle eastern garb. Primarily Maghrabi and Andalusian - http://witch.drak.net/linah/courtyard.html