SASless
An interesting question .
If she is looking looking for something that most people will be able to fly Contra rotors as has been said is the way to go .
Indoor models only are perhaps a good choice as well , tend to be light and relativley strong , but cant cope with even a gentle breeze .
You want something as has been said with all spares reddilly available like Esky products . Direct imports from China may look cheap but spares can be difficult .
Something with a basic swash plate giving a full range of control movements is also good especially if people want to progress onto bigger single rotor machines .
I had an eflite MCX that i bought to fly in the houser when the weather was too bad to fly my I/C Helis . Great fun and the only issue I had was that it was too stable . I swapped it for the MSR its single rotor reasonably stable can be flown outside if its calm but perhaps not an absoloute beginres model .
Thes things aint that cheap though !