Fender Mustang headphone amp with Bluetooth $120 Rechargeable battery!
If you want booteek…Darkglass Element $280
I already put my .02 about this earlier in the thread, but this is seriously one of the best purchases I've made as of late. The only cable to worry about is for your headphones. No dongles, no software, just pure direct tone from your bass and bluetooth that is super simple to connect to the device of your choice. If you're just trying to practice along to some music then a device like this is all you need. I know Nux and Vox also make them as well, but the reviews for the Fender are consistently better and the thing just works. I've run the iRig stuff before and it's a hassle having to connect to the phone and the app before you have a chance to even hear your bass, plus those stupid adapters break by just looking at them wrong.