I am sure you are a great person and you mean well with your intentions. This forum will eat you alive with a question regarding pricing of services that requires a legal license from your State. Training on fertilization and proper knowledge of herbicides is learned first---then you will have yearly continuing educational courses to follow. Some states require working for a licensed company for a few years before sitting in on the exams. Kind of like for plumbing and electrical.
Members on this forum will not answer your question with direct answers, so please understand that members like myself cannot and will not advise you to apply anything that will result in revocation of your priviledge license......if you have one in your town, city or metro area.
First things first.!!