Otherwise, I sometimes send them a card at Christmas-just a card.If you want to give them a small gift (gift card to a grocery store or some flowers), go for it. 

Win-Win situation if it's not mandatory that I provide it.

I never have more then 2k in credit card debt that I zero out monthly.

Some personal favorites: Start with Why by Simon Sinek, Never Split the Difference by Chris Voss, Think and Grow Rich by Napoleon Hill, How to Win Friends and Influence People by Dale Carnegie, Talking to Strangers by Malcom Gladwell.

To accomplish getting more time, one could use credit cards and credit from large box stores like Home Depot to buy materials on 30 day credit, but the labor is going to likely need to be paid right after completion from the contractor.

I am trying to learn as much as possible about coming up with offers that allow everyone involved to walk away with a win, as I get closer to closing my first deal. 

do you have a credit card with a 20k limit?

You can send thank you cards and tip during the holidays to demonstrate that you value the relationship, etc. 

Will debt payments of $2830 for your primary and $900 on your student loans (plus anything else you might have...car loan, credit card, etc.) leave you any room to finance an investment property?  

Background check shows credit card existing for a year that is paid on time.