While Pokemon Go is a free-to-play game, it’ll soon have a premium physical accessory that makes it possible to play without pulling out your phone. It’s priced at $35, but if you want to guarantee one for yourself when it launches, you’ll likely have to pony up a fair bit more than that.

Pokemon Go Plus is a Bluetooth device that connects to your phone and offers notifications (through vibrations and its LED) about various things. These include alerts that you’re near a PokeStop or a Pokemon waiting to be caught; in the latter case, you can simply press a button on the Plus to throw a Poke Ball. The device launches on July 31.

If that sounds appealing to you, you’re not the only one. Preorders for Plus sold out at Amazon, GameStop, and elsewhere ahead of the game’s recent launch in the US. As pointed out by Forbes, this has led to an influx of people who secured preorders now selling their yet-to-be-received devices on eBay. And, of course, they’re selling them at a massive markup.

Successfully sold listings for the $35 device include those sold for upwards of $100. More than a handful have gone for over $200, with a bundle of two selling for $385. Before you get outraged, though, it had free shipping. So, you know. Pretty good.

Representatives for the game were unable to share any new information with GameSpot regarding when more Plus units are expected. It’s possible it will be only a short wait after the July 31 release–in which case those spending hundreds will be kicking themselves–or it could potentially be much longer. We’ll report back when we have any more information regarding their availability.

Pokemon Go has been available in the US for less than a week but has already proven to be a major sensation. It’s added billions to Nintendo’s market cap and has been sitting atop the iOS App Store charts since its release. Impressively, it’s doing this without something as seemingly essential as trading, but that and other features are on the way.