First time orchid buyer - please help

[neworchidbuyer]

I bought my first orchid yesterday and am fairly intimidated by what I've read on this site. Are they really that hard to grow? I found it in a clearance basket at a grocery store for $1.98, and the little tag says OBrsdm. Shooting Star (Mustard). It is in a little plastic square pot, has several healthy leaves, one even has a new leaf poking up through it. There is a long (empty) rod-like thing that used to have blooms on it. Obviously, I don't know the first thing about orchids, even the names of the plant parts. I've read enough to know they like shade and humidity; but when do you know when they need repotted? Any tips would be much appreciated. Thanks,