You do not need to
buy airlocks. An airlock
can be anything that keeps bugs out but lets gas escape. Such as:
• a
cotton cloth covering tied with string
• cotton wool stuffed into top of a jug
• plastic sheeting or piece of plastic grocery bag
secured with rubber band, but don't use bio-degradable plastic if you
are bottling wine or intend to keep the airlock or piece of plastic on
the bottle for any length of time.
• put the lid on a teensy bit loose
• put the lid on securely and remove it once or
twice a day (don't use this method if brewing in glass, as it could be
dangerous if you forget to burp the bottle daily.)
• a coffee filter
• a large wooden lid put on top of a wooden barrel,
held down with a stone