Because you are asking, I am assuming that you are not a caterer....
Not trying to burst your bubble, but...... We live in a litigious society today, one does not actually have to get sick, but merely claim that they were sick to open up a nasty legal battle for you.
If you are planning on catering an event, even for a friend you should be aware of the laws and the risks involved. By ignoring these and not investigating the legal requirements for any event, you are putting yourself at a great risk. Ignorance of the laws and regulations are not a defense, in fact it will just help to build a stronger case against you if something should go wrong.
First: Will you be operating within State, Local, and Health Department regulations? Do you have a business license, a food handlers permit, and will you prepare the food in a health department approved and inspected commercial kitchen?
Second: Are you incorporated to separate your personal assets from being seized. Do you have the proper liability insurance to cover you and the patrons?
Be aware that without these two primary items being fully covered, you are taking a huge huge risk both personally and financially.
Sorry, just want you to be aware of potential risks....
If the place/person you are cooking for has all the above legal requirements, have them put you on the books for a day and have them rent your smoker. That way you are an employee and you are using their equipment at that time, thus leaving the bulk of the liability on them.
You should really check prices in your area, but here the average price for St. Louis Ribs run about $17.00 for A la-carte.
Keep in mind that baby backs typically cost more than the price of St. Louis cut ribs...
here is a menu in Conway.
http://www.wholehogconway.com/menu.php