I've been very heavily involved organizing 2 craft fairs a year for a non-profit for the past 3 years. 2 ballrooms - 85 vendors - 125 spaces. It is a lot of work! Don't forget there are some venues that require "event" insurance that would cover injury liability. Free publicity is usually reserved for non-profits. Even if it's only a small fair (20-25 vendors) you will still need someone to man your space while you are tending to other things; it's difficult to set up your booth while answering questions or giving directions. If there is a Farmer's Market in your area you may want to contact them and see if they (or their vendors) will help advertise. Another way to get free advertising is to ask "clubs" (American Legion, VFW, Rotary, etc) if they would mention it in their newsletters. You would need to get all the info to them 2 months in advance. One piece of unsolicited advice: Don't charge for admission; people will pay to enter established fairs with a great reputation but won't for a new event. Wish you well!