"Dealer sample items have 50% - 70% discount"
Whoever told you that is a f'ing liar. Sure it's 50%+ in something like the HVAC business. Not in the firearm industry. On guns it's very low(sub20% if you are very lucky), on ammo it's practically non-existent, on parts it's somewhere under 50%(more like 20%).
One of the biggest disadvantages for a home based person is keeping their inventory squared away and separate from their personal guns. When I take a personal gun into my workshop, I need to tag it so the ATF doesn't stop by and assume I have extra guns I'm selling that aren't on my books.