Want to stop dandelions and broad leaf weeds in your lawn in the summer while saving money . Put away the weed killer and weed stop fertilizer. Just start mulching your fall leaves into your lawn. I have proven with my lawn (seen below) that when I mow/mulch my maple and oak (oak leaves don’t make your lawn acidic see http://www.greenmichigan.org/green-tips-how-tos/leafleaves-chart-for-lawns-and-composting/ ) leaves into my lawn I had 80% fewer weeds the first year in my lawn in the spring and throughout the summer. Now after 5 years weeds are non-existent and I have a beautiful lawn.
You will also save money by not paying leaf clean up and cost avoidance of the weed killer.
Do not just believe me see this MSU article and study
OR this technical article