What should I wear to my job interview?

guest

I don't really have any formal or professional clothing. It's a laid back office. It's a receptionist position. The current receptionist and the woman that interviewed me were wearing jeans and ugg boots. But I'd still like to come in professionally. I have a pair of slacks but they aren't the right size and are really big on me. What should I wear? Can I get a cheap outfit somewhere? If possible please post examples