The guy I was using to treat my lawn sold his business over the winter so I'm going to try DIY this year. I was paying him around $300/year to do the green dye spray 3x, fertilize 2x, and then spot treat weeds as needed. I still had to pull some weeds during the summer so I guess his stuff wasn't very good.

Is there some law that prevents me from buying the stuff that the pros use? I know Home Depot sells the basic stuff like "crabgrass killer" and "weed and seed" that you spray out the end of a hose, but I get the impression this stuff is weak to prevent consumer lawsuits.

The lawn is 99% Bermuda in central OK so we get hot dry summers.

Also any recommendations for a good fertilizer? I pH tested the lawn in various places a while back and it's all within the normal range so I don't need any supplemental minerals.

You want something with high nitrogen, since grass relies on nitrogen to be green and lush. Nitrogen is the first number in a fertilizer mix xx-xx-xx. A bag of urea 46-00-00
Would make it nice and green.

Don't know much about growing grass overall,but I work in the agri-services business and corn is of the grass family and it requires nitrogen.

You can add other nutrients as well but nitrogen is going to make it look the best.

Check a farm co-op or similar.

Start here Bermuda Bible

The pre emergent herbicides like Barricade are for crabgrass et al. You will need that plus a broadleaf weed control, such as Dicamba, to whack the dandelions in the spring. I prefer to go easy on fertilization as too much just means you mow more often.

If you are looking for pre emergence for weeds, look for something with active ingredients called pendimethalin or prodiamine.  Both are good for crabgrass, many other grassy weeds, and most broadleaf weeds. Best to apply it late fall, and again this time of year to get good control through the summer. If you are lucky enough to live close to a John Deere Landscapes, formerly lesco, I would suggest going to them over home Depot or Lowe's. Also co-ops are a good place to look.

Beat me to it. Barricade is the trade name for the prodiamine chemical I mentioned. Also used in a product called stonewall.

We were out chipping ice around the cars this afternoon.  I assume there is still a lawn under the snow