He originally had it for $400 with free shipping. Back in April (2021) I asked if he would accept $350. He said yes and dutifully lowered the asking price on his eBay ad to $350, but at the same time added the ~$50 shipping fee, which when I discovered that duplicitous action really annoyed me. So I "walked away" from that potential sale and in a couple of months found one a lot cheaper elsewhere.*
Nonetheless, this appears to be new and at ~$400 + tax is somewhat less than Tesla's asking price (is it still $450 + tax?). Perhaps you can talk him down? He has had it for sale on eBay since at least April 2021. Maybe he will now be more motivated to accept a lower price? (Or not. How much does it cost to advertise something for six months on eBay?)
I'm not advising you to buy it; but it is the only "new" one I've consistently seen. Most sales I've seen are indoor covers, used (which could also be OK), for other Tesla models, or aftermarket.
I can say that the Tesla cover quality is excellent, it has outer weather resistant layer and inner soft paint-protective layer, it fits like a glove (use exterior mirror fold-in feature to make installation and removal easier), and that installing and removing becomes easier once you do it a couple of times. Very protective against sun, birds, paw-prints, etc.
* I was fortunate in being able to find an unused one (with carry bag and in original Tesla box) "locally" on Craig's List. I'm near Sacramento, CA; the seller was in Reno, NV; not that far. He wanted $200. Good price. And he conveniently shipped it to me for $32 (saving me the 5-hour, albeit beautiful, round-trip journey). So I lucked out. But imo $300 + shipping + tax would be a good deal for a truly new one. I relate this story to you to promote and encourage the use of Craig's List, which I find if you are careful often works well. So along with the TMC Forum Marketplace use CL to search your larger nearby metropolitan areas. You can create and save custom searches on CL that will notify you (by email) whenever there is a "hit" on your searches. Very handy. And, you can also use Google online to search for something like:
"model" | "tesla" "x" "craigslist.org" "car cover" -inside
(the "|" sign means "or") to search nationally for Model X outdoor covers. Some CL sellers will ship if you pay safely with PayPal or something.
If you mean the $130 one in Maine, yes that was a good deal for a decent used one. I think I had also corresponded with that seller at some point and he seemed like a nice guy. It had some stains, but no big deal--I've found that tom cats love to mark the giant cat pedestal on their nightly forays. (Ha, ha.)
Or you probably meant the $380 one, which was new to me. A little high, but with free shipping. It also looked good. Yes, I would have tried to talk him down and probably lost that sale to a B-I-N buyer, also. (Maybe the Florida seller will learn something from the relatively speedy North Carolina sale and lower his overall combined asking price?)
Don't give up. With eBay, TMC Marketplace, Craig's List, and maybe Reddit "TeslaClassified" subReddit you should have a good chance to find one at a discount in time.