I know of lawns in NJ at $25, in urban areas or townhomes and up to thousands of dollars a month, for estate maintenance. A good formula to go with is; labor + material + overhead + profit = a fair & justified price. You don't need to price what the other guy does, his price, like yours should follow a fair formula. Labor costs will be dependent on time spent, who & how many. Materials for lawn maintenance can be broken off to include consumables, like fuel & trimmer string, or if that is your primary business, included in overhead. Overhead will be the number it costs you to be in business, (trucks, machines, computers, programs, rent, utilities, licensing, insurance & all that business stuff) broken down by months, days or even hours. Profit should be a number that is included in the bid, not how much might be leftover at the end of a job, day, week or month.
Determine how many guys, for how long, with what equipment, include what it costs for you to do the job, and how much your business should make. You may be able to calculate a sqft price from this, but unique circumstances may alter the price at each new location.