You'll need to learn a little about the customer so you can appropriately market to them and about the product, but contacting suppliers, negotiating discounts, doing sales projections, blah, blah, blah, it's all the same.

I would just investigate the prices for things that you know happen (from your current supplier), or even go off of your chart of charges you use for move outs.

But in the mean time supplier has to be paid , subs have to be paid , employees , salesmen , and office staff , etc. .

I've tried numerous forms and work orders to keep my maintenance staff on track and detailed in how long the tasks take, what parts they used, where the parts came from (ie stock or supplier), etc; but I always end up with missing information.  

Ideally, get a separate meter and separate account with your electricity supplier. 

If you have time on you side you can order onlinefrom electronics   supplier like digikey or mouser. 

Usually it's paper side toward the insulated space, depending on your area, but for humid areas with A/C it may be, paper toward the heat, check with your local insulation supplier .

Anybody have any experience ordering cabinets and plumbing supplies from Barnett Supplies out of Florida?

All my subs and suppliers are always relieved when they learn a place is on lockbox.

Private loans, a 203k fha buyer, title one loans, suppliers that will carry, credit cards, car loan, internet loans like prosper, a one time partner,etc,.etc.