Online Selling "For the Birds"

Over the years I have dabbled at online buying and selling... mostly just buying things for around the house but occasionally selling things I no longer need.  I never actually made any money selling but it was fun when I was able to get a little bit of money for something I would otherwise just have thrown away.  If only I could sell something in quantity at a price that would give me a little extra pocket change I would really be happy.  It used to be pretty easy to sell stuff online but nowadays it has become really competitive because a whole lot of folks have the same idea that I have.  I figure I need to come up with something new to be even a little bit successful at it and I think I may have some ideas... maybe.
Last month I was getting my bird feeders ready for the season and I thought maybe I would upgrade my feeders since they were all so old and in need of retirement.  I was looking at hummingbird feeders when I noticed these big domes that hang over the hummer feeders to keep the midday sun from getting the nectar too hot and to also keep the rain off of the feeder.  I thought this was a great idea but the prices are outrageous.  I began to wonder if maybe I couldn't put something together myself that would do the job and save a few bucks.
After giving it a lot of thought I came up with a design that I figured would work and ordered some parts to make a few.  I would try it out and if it didn't work I wouldn't have lost too much.  And who knows?  Maybe it might end up something I could sell on eBay.
I made a "Big Red Dome" and it worked great.  It cost more than I had figured it would but I had enough parts to make a few extra and put them on eBay and they sold pretty quickly.  I ordered some more parts and sold some more.  Then I came up with a design for keeping the rain off of my dry feeder and made a few of them.  I found that both designs also are pretty good at keeping squirrels from getting on the feeder and that the folks that bought them loved them.  So, I will try to see if I can get the parts at a cheaper price and maybe make enough to pay for the gas it takes to drive the two miles to the Post Office and back.
Enter the ants.  We have a lot of ants around here and I guess that just about everyone else can say the same thing.  I built some ant moats a few years back out of empty tuna cans but I figured if I could come up with a better design that might be something I could sell online also.  I spent hours and hours looking all through the listings on eBay in search of something I could use as a basis for a new design and the only thing I found was a stainless steel cup that holds 2.5 ounces, but it looked great.  The only problem is that stainless steel is VERY difficult to work with.  I bought some of these, some stainless steel tubing, some stainless steel hooks, and some silver solder and went to work.  I finally succeeded in getting some made and, if I do say so myself, they came out pretty nice.  I put them on eBay and they sold immediately.  In fact, the folks who bought them wanted more... so many that I couldn't keep up with the orders.  In fact, I soon realized that I had created a monster because these things are a pain to fabricate.  Maybe I could just patent the design and sell it but I doubt it.  The manufacturers these days don't care about quality... they can make big bucks just selling plastic ant moats that need to be replaced every year or two, so why make something that will last for years to come?  Oh well... like I said, I have created a monster.
Anyway, I will continue to sell my "Big Red Dome" and my aluminum "Rain Guard" and maybe the occasional "Stainless Steel Ant Moat" on eBay but I don't think I will be getting rich any time soon.  At least I have a hobby that will benefit the birds, and when you think about it maybe that makes it worth more than a few bucks.