Instead of telling you step by step to do something I'll share what I did for some extra cash. I use a eBike to do some side jobs. I built it from parts I found on eBay (x2 1k watt dual sync hub motors, large range battery pack, misc. computer and controller parts, etc) and a name brand 7 speed bike I find at locally (last time was Walmart). I don't shop based on "cheapest" but on what name brands ppl will recognize when they are shopping for such a ebike. My goal is to turn a $750 investment into as much money as possible.
So I want a nice $250 margin to make my "final" parting value $1,000. I then multiple this by 3X to get $3,000 Retail. I am selling my eBikes as used, even if they are new. My ebike is outfitted with a nice battery pack for 50+ mile range, dual sync 1k watt hub motors with controller, throttle, chain addons, mounts, etc. I created a product from parts I found, put them together, then decided my margin and retail pricing. Why do ppl want my ebike than xyz ebike? Simple, I know how to sell to ppl that want that nice blaance between cost, saving the planet, and function. Next is understanding the competition and the "savings herde mentality". I can make my ebike out of cheap China style parts OR play up on name brand American parts, etc. I can also say that the eBike is made in America, just not the Hub Motor. I am upfront and honest about all the parts, there is no need for deception. My parting price for my ebike on Facebook / Craigslist is around $1,000 minimum. My last 3 ebikes sold were around $1,300 average. It took me around 350+ different ppl, around 20+ scammers, etc, to sell my ebikes. Why? It's natural for ppl who are looking to kick tires because of the price commitment. I switched it up and put my gimmick (secret sauce) on the eBikes saying that they were perfect for eco friendly in town work and commutes. I then offered ppl to help determine whether the ebike was good for their usage or not. I simply devoted some time and sat down, wrote out any and all information I could on the eBikes from Google Maps routes to money savings guide to wear and tear with gas and parts cost on cars, etc. Now I've sold a total of 5 eBikes, with tire kickers wanting around 2 more that are listed (no sales closed yet).
Why give my niche? It requires a brain, it can't get over-saturated because I am directly targeting locally in my area, etc. It took me a brain, a few hours of patience each ebike, and start up capital to make the ebike and sell it. If you really wanted to go dropshipping route (you will get fucked over on prices) then it could be possible with less margin or no margin. Why? eBay and Amazon both suck for selling ebikes.