If you to want wear the orthotics while dancing, putting some suede soles on sneakers may not be a bad way to start. With the cost of actual dance shoes these days, it may end up being the cheapest solution, too (dance shoes may not function as designed when filled with that much extra material, so getting them oversize enough would be an expensive experiment). There are dance sneakers made, and often no more expensive than ordinary ones, but their flexibility may be at cross purposes with the full orthotic, so unless you can try them out at a local ballet store there's no need to pursue that over a sneaker you already find comfortable - and most would still need the soles replaced. Later on after you have more experience with dancing and an idea of to what degree you will want to use your feet, you can look into other options and tradeoffs between flexibility, padding, heel height, etc and perhaps eventually use a cushion insole rather than the orthotic when actually dancing. But for just starting out, the only "dance" requirements are that you are able to be stable with your weight both to the front and to the back of the foot, and that you don't stick to the floor - the rest of the requirement is what you are comfortable with.