I fully uderstand. I see things in other online pet stores with a major markup and I think - Hey I could sell that. But then with all the costs incurred. I am staying with things either I or someone close to me makes.
I may not make a ton but I would rather have great repeat customers that refer me.

As long as I cover costs and have some fun $.
As far as stealing Ideas. I know of at least one customer that purchased a dress and a few weeks later was selling the same dresses on line
Gosh - at least change the pattern to make it your own.