I would think about what it's going to take to get started in any full-time business. Premises, utilities, display/photography, marketing, clerical stuff (an accountant?), supplies/equipment replacement and maintenance, loss of the time you used to have and THEN the cost of living you think it really takes.
For myself and many others a home based business doesn't mean the premises are free. At least one room is going to be devoted to your business. If you decide on a brick and mortar store double your expenses. For me, utilities are high. Gas and electric add up. When you decide to get serious a professional photography setup is a must, preferably attached to someone who knows what to do with it. How much does printer paper and ink cost? A whole lot if your hard drive or motherboard crashes. It's going to happen. Plan. Supplies and equipment - supplies are thankfully pretty stable right now, but if I want to go full time I need a new torch and kiln and tanked or compressed oxygen so I can produce enough to pay for everything. Ka-ching. I work 12 hours a day, 7 days a week. I pay myself for about 4 hours a day. You can't do that if you plan to make a living at it. Health insurance. Not going there. Can't wait to see what Obamacare winds up costing me. Judgement against me? Take a number. Just plain cost of living: every month I sit down and figure out what I spent on groceries, rent, gasoline, clothes and incidentals. Every month I vow to live on breakfast cereal (without milk) and live like a hermit.
If you are serious about quitting your day job, do it. Not because you're going to make what you need online. Have a family you need time for. Have health problems that prevent you from working (God forbid) but don't do it because you think you'll be able to strike it rich online.
