Checkout Weshauffer. They have a small 200 gallon skid setup that uses a 12 volt pump, comes with 300 feet of hose on rewind reel and all. Ideal little setup for just spot spraying weeds and using granular fert apps.
I went with same setup only with Honda motor and a pump capable of 550 psi, OVERKILL. The 12 volt setup would have worked just fine for me and would have saved me about $1,200.
I do use a hose end sprayer on mine. This allows me to just carry water in the tank. I can change and spray different chemicals all from the same tank with just one visit. Keep in mind I do not do a vast amount of lawn spraying. I only spray with this rig when I cannot do it with a backpack. So if doing alot of all spraying you would want a chemlawn gun or equal.
But, in my mind granular fertilizer and liquid spot spray is a better way to go. In my opinion it is better for us as applicators, better for our egology, and better on our pocketbooks.
West Lafayette, Indiana