I would make this "A destination" event. Hold weekly sessions that last a couple of hours. Start with a model kit that isn't overly complex. Quick build and finish for perhaps, shorter attention spans (?) to start with. Work your way up to the 1/35 Academy Tiger I with interior and metal tracks.
You might contact companies like Round 2 or Atlantis Models to see if they will consider participating in supplying kits at a substantial discount. Beverages and bathrooms for the junior model-makers. Home in time for supper.
The better builders will keep coming back while the less dedicated kids shine you on in a short amount of time.
Included the starter kit at no charge. Sell a more complex, interesting, fun model for a % off retail.
Your time and your expertise are valuable. I advise against giving it away for free. That, and your own model time will VANISH as $$ roll in!
After lunch and before supper. You don't want this to become a daycayer occasion. Offer coupons to parents for Fartful Barn discounts on different retail items on different weekdays. Build the "Destination" see? Create your own traffic. Give people an interesting reason to visit The Fartful Barn!
Could you interest Local Clarksville wimmin-folk in pottery/painting classes too? A seminar? Get the $$ up front, so if people miss the seminar, it isn't a financial disaster? Complimentary, local wine for the Moms? "Oh Gail! I have a job for you!!"
Hit the local winery up for a discount too! "It's for the fun of creativity!"
How busy do you want to be? Choose, but choose wisely.
Hy-Vee does the coupon thing to keep people coming back to the grocery store every day. I think it's insidious, but it works on a certain mindset of person. "The common clave. People of the Land. You know. Morons."
Above all remember: No Good Deed Goes Unpunished!
Howzatt?!?
guess:
