I would like to know some investors that will let me use their money for free. If they exist, they are not very smart.
Some dealers might would give you a cash price and then allow you to take advantage of a 0% deal but they will pay the interest for you up front to the bank. If you really pay cash they make a little more off the deal. They might would do that because most deals made with lending companies include a end of the year rebate to the dealer. They will make it as attractive as they can to take advantage of the rebates.
Most of them will offer a free loader for cash deals or conventional financing. But when 0% is on the table the free loader goes away. But that loader is still not really free as it is built into the price to begin with.
In my business, we get rebates from lenders all the time for bringing them business. We also get rebates from manufacturers. Some dealers will play the rebate game and sell product at ridiculously low margins and rely on the rebates for profits. This never works and these dealers go out of business with time.