Do apps use mb from my internet allowance?

[Retallica]

I've got a HTC ChaCha and i've downloaded a few apps. The phone also uses fb chat and shows updates from facebook. Does this constantly use mb from my internet allowance? I get 1gb of internet a month. And do apps such as Touch (formerly Ping chat) use it constantly? And does it get used when connected to wifi?

Thanks in advance!

[Andrea]

If your data is on, yes. If you're just on WiFi, no.

[Maria]

If youre on wifi it doesnt charge you. 1gb of data is alot and you probably wont go over your limit.