Variable expenses are those expenses that track directly with sales. If sales stop they stop. These are expenses like supplies used to support in the making of your product or doing your service. Such things as shipping cost for raw materials for your product or service. If you have no sales then you're not going to be purchasing materials so your shipping cost for those materials will stop as well. As an example, if you have a lawn mowing business and there are no lawns to mow, then you wouldn't be buying gasoline to travel to your lawn mowing site. These kinds of things are variable expenses. If you're producing a product, it would include supplies used to produce that product like sand paper, glue, finishing materials, cutting tools, etc.
So, why not start out with what you would like to have in life for you and your family? Then develop a business plan that could show you exactly what your business would need to do to give you that life style. If you think about it, there is no other way where you have more control over what you want in life than letting your own business do it for you. If you work for someone else, you're sure not going to have as much control over your future. So how would you go about making a plan like this? Well if you know a fair amount about business, you can. It will take some special calculations and some work but if you know how to put together a Profit & Loss Statement, you can probably do it.