"The Wal-Mart ballet flat is a great idea. They cost like $7.50 you know the kind of slippers your grandma wears all winter.
Honestly I wouldn't start out wearing heels."
I would agree there is merit in not starting out wearing high heels, but it is essential that the shoes have a defined heel on them. The problem with ballet flats is not that they are flat but that there is no definition to the heel, so the dancer is reluctant to put her weight there, which is something that she absolutely must do at times in the waltz, foxtrot, etc type dances. It's fine to start out with low heels comparable to what the men wear, but the shoe needs to have something solid under the heel there. When you see a woman dancing in ballet shoes, you never see her properly using the entire length of her foot, instead she is stuck on the ball-toes region only.
For investing in actual ballroom shoes however, at a minimum the student should wait until she understands the functional difference between latin shoes and standard shoes. Each is a poor fit for the opposite style of dancing and will cause some real consequences and limits on learning progress, so it is necessary to decide if you want to compromise on one style or the other to save money, or to ultimately buy two sets of shoes, or to buy some of the less stylish lace up shoes that "sort of" work for both. Those are not decisions that should be made before at least a few week's experience has been gained - experience that can be built wearing anything sturdy with a bit of definition to the heel and not too sticky a sole.
