Anker has been producing Android-based portable projectors for a few years, and the Mars II is one of the company's more powerful units. It originally cost a whopping $500 when it was released in late 2018, but now you can get one from Amazon-owned Woot for just $349.99.
The Mars II is a 300 ANSI-Lumen portable projector, capable of creating an image 30-150 inches across, with two 10W speakers for audio playback. The 1280x720 resolution might sound low, but when it's projected onto a wall a few feet away, it looks just fine. The Mars II also has a 12,500mAh battery, which lasts around 4 hours when watching movies, and there's even a mode that turns it into a beefy Bluetooth speaker. You can read our full review of the projector here.
As for the software experience, the Mars II is equipped with a heavily-modified build of Android 7.1 Nougat, with access to the Aptotide app store. That means you get a mix of TV and phone-optimized apps, but most popular services work to some extent: Hulu, YouTube, Spotify, Plex, Amazon Prime Video, and so on. Worst-case scenario, you can connect a Chromecast or other streaming stick to the projector's HDMI port.
If you're looking for something more compact, Woot also has the original Nebula Capsule on sale. It has a similar software setup to the Mars II, but in a smaller package (with a much dimmer lamp). We have a review of that model too.