When I hear "affordable" I always think, undesirable since price is always based on supply and demand.

Not a problem for one QB Desktop subscription, but after I added it up, including one $200/month subscription, we would have had to pay nearly $5000 per year in QB Online subscriptions to match the capability of QB Desktop!!!

I do not understand why one looking for a buy would ever go to a "wholesaler" vs those who actually control the vast majority of supply. 

My friend is going to supply the money for the down payment.

There are suppliers in China who can supply pre-cut SIPs and they say they can source other exterior and interior finishes (except electricals and plumbing) from other suppliers and ship it.

I was concerned because the tenant has roofing supplies all over the back yard in addition to a trailer and roofing machine in the street. 

You can ask the Sub's, or whoever you are going to do the work, which materials they need and price them out at other supply houses.

Plus the resources Africa supplies.  

I have done wholesaling in the past (not in RE, but in reverse supply chain liquidation), and had to deal with a lot of unethical and dishonest sellers.

At the time I didn't really understand why, since you had to pass the income and credit checks regardless and there were only 2 companies that owned all the upscale places so not a huge supply.