Welcome Diego! Best advice I can give you to not lowball, is to survey the lawn for what it is every time you look at one. Trees, flowers, shrubs, hills, amount of trimming etc...take into account what each property has! I never go below $30 no matter how small a lawn is, if that's too much for someone, politely remind them they will get what they pay for or just say, ok thank you anyways, and move on. I do give a few different discounts, a military discount, also a regional discount if the property is close enough for me to drive my mower there alone, a few houses down or something, I offer just a tad bit cheaper than normal. Get some shirts and business cards for sure. As far as mulching I always charge by the yard. Weeding, and other things I do by the hour by employee. I also use three great apps on my iPhone, one called "invoice" to send quotes and invoices, one called Venmo which allows me to accept debit and credit, and one called mile bug to keep track of mileage for tax season. Hope this helps.