If you want to protect the bottom, you might just glue a piece of leather or pleather to the bottom instead of more fabricy stuff, which would also stiffen it some. You can get a used bag or something from the thrift store instead of buying a piece of leather. You can get actual bag feet from a craft store or online, or you can get creative and find 4 doohickeys from the hardware store to plunk on the bottom.
Optionally, you could cover a plastic embroidery rectangle with fabric and just place it on the inside/bottom, then just use feet on the outside/bottom.
It does look like they were sewn in some way there, could be a serge. You could probably just do a sewn hem (if you don't have a serger or other acceptable). I'm guessing the tatter effect is made by a sort of inverse scallop pattern along the bottom, and sewing a hem along a continuous curve can create a ripple effect. A serge stitch or equivalent would probably be easier, though, and look better on both sides.
Unfortunately, when it comes to crafters' online stores, etsy already exists, the top sellers are craft suppliers, and etsy loses money every year even though they now embrace "cheap stuff from China" to keep themselves from completely drowning. They have a history of losing money. Last year it was a whopping $15 million. Ouch.
So, all being fair in business, I have questions for you, the first being "Do you understand the first paragraph?" and more questions would be:
Are trying to become the next etsy? Why do you see the handmade "community" as a money-making venture? How do you plan to revert traffic from etsy to your site? Supplies sellers are going to stick to etsy where they make money (because... traffic). How are you going to make up for the loss of these top sellers?
If you don't make money, you'll close down your site and leave all the folks signed up without a store. How do you plan on making money? Yeah, big secrets, I know, but I've seen dozens of etsy-style startups come through thinking there's a gold mine in the craft market. I don't think the gold mine exists.
When etsy first started up, this forum was near to bursting with excitement, questions, and traffic. But having an outlet to sell is one thing. Actually selling the stuff is where crafters gave up and died off. So the majority of your initial sign-ups would be from folks who are looking for a deal, which I'm guessing you'll give them just to get your project off the ground. Therefore my last question is: How do you plan to convince sellers to engage in selling? Because they won't do it without a serious kick in the pants.
I think they both have their appeals. And now here I am, stating that putting words on things is sort of like trying to selling a greeting card with only one message on it, rendering it unbuyable. When people put words on their art it sort of takes away from my interpretation of it. Like all the really nice things at the home store, then somebody slaps "dream" or "inspire" on it, rendering it unbuyable. At least to me. So don't put words on every piece.
My dad would always to go the lumber store to get his stuff and saw off what he needed, but then he had a garage full of power tools and knew how to use 'em. If you're at the point where you're serious about providing quality wood products, learning how to DIY raw wood or lumber is an awesome skill to have. That way you can design the product, measure it, cut it, put it together or into a kit without having to pay the middlemen. Good wood and woodworking labor is never going to be cheap.