squeaking ratty

Question
Hi,
I got my second rat about 2 months ago, and I'm not sure what to make of
her constant vocalizations. She will constantly make a high pitched chirping
sound when she is not provoked (my other rat will often be nowhere near
her). Usually, if I come up to the cage, she will stop, which makes me think
that she is not coughing because it seems that she has control over the
sounds she is making. I have been looking all over for some kind of explanation, but all I can find  on the topic is rats squeaking when they are
being groomed,fighting, or otherwise provoked. My first rat really doesn't
squeak-only sometimes she will make a relatively low grunting noise when
she is sleeping...maybe she's snoring or having a nightmare?
I will gladly take my rat to the vet...however, I am pretty poor, and even if
there's nothing wrong with her, I'll still have to pay the vet at least $100 for
the visit itself. So, long story long, I'm looking for some advice!
Thank you so much.

Answer
Is she acting healthy? Coat, eyes and ears look normal/healthy/fine? If she's acting fine, still eating and drinking, has no discharge (yellow, white, green, red or otherwise) from her nose, mouth or eyes, I'd say she's probably just a chatty cathy and you probably don't have much to worry about. If it sounds like a pained cry, take her to the vet and have it looked at, by all means - but I've met some talkers in my day, and even my vet has said its just.. them.

Hope that eases your mind some!