Jen, that's correct.
Yogurt has very little lactose in it to begin with, because it's often broken down in the process of making it.
My mother enjoys making home-made yogurt. She typically buys a small container of greek yogurt and uses either whole milk or 2% milk. Heats up the milk to the right temperature, ads in the yogurt with live cultures, then continues "cooking" for another 8 hrs? She used to use a yogurt maker which keeps the milk at the right temperature, but has since switched to a modified ice chest with heating pad, which keeps the milk/yogurt at the correct temperature for the required time. She uses large glass containers from the dollar store, and 1 gallon of milk creates about 4 containers of yogurt? If she wants to remove the whey from the yogurt and make greek yogurt (which she often does... whey is sour/bitter, and removing it from the yogurt makes the yogurt much less sour/bitter tasting), she gets a colander, lines it with cheese cloth, and sets that over a plastic container. She most often covers that with a plate, and when she wants to remove the yogurt, she either scoops it out or flips the colander over onto the plate and peals the cheese cloth off.
You'd be paying about $2-3 (max $5?) for the gallon of milk, and $1-$3 for the small container of yogurt... plus the supplies if you don't already have them.