France began providing arms and ammunition as early as 1776 (the war started in 1775). In early 1777, months before Saratoga, the French sent American colonists 25,000 uniforms and pairs of boots, hundreds of cannons, and thousands of muskets -- all stuff that the colonists would've had a hard time surviving without, and all stuff they had no access to on their own. And that was just the tip of the iceberg: From supplies to advice to military reinforcements, France exercised all the fiscal restraint of a drunk businessman at a strip club when it came to funding the American war.
France provided a whopping 90 percent of the rebels' gunpowder. Let that sink in for a second. Without France, the entire American Revolution would have devolved into a bunch of dudes swinging their muskets as clubs within weeks.
Still, the most important French contribution to the revolution (or, if you're British, their ultimate dick move) was the least visible to Americans. As mentioned, the reason France pampered the Patriots was always selfish. They were out to weaken the British forces -- particularly their naval strength -- in order to take the fight to them, perhaps even conquer them. That's why, for much of the Revolutionary War, the British ships tasked with kicking America's ass had to survive 12 rounds with the French navy before they could even think of crossing the Atlantic. France gleefully fought the British, eventually teaming up with Spain, declaring a war, attacking from all sides, and even setting up an invasion force. In those battles, America's independence was a fart in the desert.
So, when the Colonial army was fighting for dear freedom, history books tend to conveniently forget that they did so with French money, equipment, and backup forces, while France and its other allies were busy pummeling the empire from every other side.