The defendant in a court of a magistrate may, on the return of process and before answering, make an offer in writing to allow judgment to be taken against him for an amount stated in such offer, with costs. The plaintiff shall thereupon, and before any other proceeding shall be had in the action, determine whether he will accept or reject such offer. If he accept the offer and give notice thereof in writing, the magistrate shall file the offer and the acceptance thereof and render judgment accordingly. If notice of acceptance be not given and if the plaintiff fail to obtain judgment for a greater amount, exclusive of costs, than has been specified in the offer he shall not recover costs but shall pay to the defendant his costs accruing subsequent to the offer.