How do I get rid of roaches?

Well I am 13 yrs old and I share a room with my 10 year old sis who is messy but I allways make her clean her mess. My family just moved into our new home on may 5. And just about an hour ago my sis and my cuzen just noticed a couple roaches or some type of bug in our room. We don't eat in here and when we first moved in our new room I can garuentee there was no roaches. Our closet has speical thingys built in that is just wood I wouldn't know how to explain it but I guess they are living under there. How can I get rid of them and how can I kill the eggs how much would this cost for my family since I don't have a job(and I promise you I want one) would cost them and what are the items we need to get