A 200 gallon 12 volt system cost how much? It will limit you on what you will be able to do in the long run such as deep root fertilizing & tree spraying, no PSI. 300 foot of hose up hill....well, I bet I could pee harder.
How is applying granular herbicides safer on the enviroment & pocketbooks than spraying? Actually, almost 100% of herbicides sprayed on the turf stays on the turf if watered in correctly, opposed to granular which is often spread onto paved aeras, shrub beds, ponds, and so on.
As for $$$, this has been covered before, Bayleton for example cost $5.65 per 1000 granular. In sprayable WS packs it cost $2.55 per 1000, over $3.00 per 1000 additional profit.
A good high PSI rig also allows you to offer other options. Deep root fertilizing cost $0.12 per .5 gallon injection,, most companies around here charge $50 and up per tree. I spoke with one member here a while back and he said he does $14,000 in about 2 weeks doing deep root fert.
My sprayer cost $2800, tree gun $107, deep root injector $150 I think, and I bought a deicated trailer for $700. Hope this gives you an idea of cost for this type of set up.