cycling: stupid bike

Yesterday the chain fell off my bike again (it does this all the time) and today it's clonking and chonking and clicking as I cycle. I know it's a cheap bike, for Christ's sake, but how hard is it for a cheap bike to do its damn job. I guess I'm bringing it back to the shop to see if they can figure it out, but this is really frustrating

What's even more frustrating is that most of the time the place behind a gate and under a roof isn't easily available at work when I arrive, so I don't even WANT a nicer bike because this one is likely to end up in the rain and possibly stolen. I just want my cheap bike to WORK.