They are right there in your house already working for you! Just offer all those part timers who’d like full time or those who are piecing together part time jobs, actual full time jobs with benefits. You may be losing more money from lost business by being understaffed than the amount it will cost to provide benefits. And you will see an improvement in morale, productivity, and customer satisfaction as well. Attributes that can’t be clearly measured but most likely result in improved sales.
And don’t forget the opportunity costs spent on advertising for help, people who don’t show for scheduled interviews, or new hires who don’t show up for their first day at work…you’ll be more productive too if you stop spending so much time trying to hire!