When I came to Japan I bought a blue $20 Sigg bottle. I’ve used it almost every day at home and while traveling. It works great but sometimes it’s a little big. I saw a 500ml bottle at the ¥100 store but it was a ¥500 priced piece of junk. The other day I was craving some Lays Salt & Vinegar chips so I headed downtown for some underground shopping and ran across a ’3 coin store’ where everything is 300 yen. I saw a Sigg like bottle that looks good inside and out and I bought it for a total of ¥315. If you have a store like this near you, or you ever see one in Japan, I highly recommend it. Will this 500ml bottle last forever? I’m not sure, but so far after a week of extensive use it’s doing good, and hopefully it’ll last with no corrosion on the inside. Here’s an image for comparison.