just get a gallon of the bug spray from home depot that comes with a sprayer handle or advise them to buy it and spray around the baseboards and doorways.

I would recommend Painter's Edge Flat, there's a wide range of stock colors that are good for flips, and it's about $12/gallon.

My Section 8 tenant's daily water usage ranges from 50 - 600 gallons per day.  

Drink a gallon of water daily. 

Do you know what size gravel you should use in your concrete, how many gallons of water you can safely add and whether or not your should use calcium chloride in the mix?

Hasn't happened since we went all tile.As far as price, I look for the best closeout I can find where they have the quantity I need and the same die lot and normally a beige colored tile to go with the other materials below.We use the same paint in all of our properties, Ultra Hide from Home Depot in an Antique White, I think it is 75 or so for a five gallon pail.

I buy the gallon and a half jug of home defense at home depot. 

I guess if you own a 4-plex or larger you are charged per 1000 gallon, 2-3 plex has the choice of metered or set.

The only one that comes from a paint store will run probably $60-70 a gallon.  

A "side effect" is that you can often charge a little more rent next tenant because you know it only uses 400 gallons of oil each year vs. the 550 it used to use.