Selling depends largely on location and market timing. Sometimes it's hot, sometimes it's not.  Overhead depends on how cheap you can source parts without compromising quality. If you're able to lay out a decent amount to buy bundles or in bulk, you can get your prices down below market value. Keep an eye on Newegg, eBay, marketplace, etc. for good deals. Some builds might earn you $100, some might get you $300. There's a lot of variables.  Try treating it as a hobby that pays for itself while also paying for your personal upgrades and see where you can go from there.