I don't know what "plan" or "insurance" you have.  Most insurance plans
covering procedures on the basis of UCR (usual, customary and
reasonable) will pay for root canals at 80% of UCR (note that some UCR
schedules seem to have been discovered in a time capsule from the time
of Ramses II)--some will pay less.
    You haven't said what tooth you are dealing with, nor why the tooth
needs root canal.  Around these parts (Brooklyn, NY) the fee for an
endodontist for an average molar tooth is in the $1000-$1200 range.
Less complicated teeth or those done by a generalist will likely be less.
    The majority of teeth requiring root canal need to be crowned, or at
least a restoration that covers the chewing surface.  This is to
minimize the chances of cracking.  Fees for crowns vary widely, but $1K
is a pretty fair guess of an average nationwide.  A post and/or core may
be needed as well.  Given this, a total fee of $2000-$2500 might be
right; out of pocket fees of $2000 indicate you're not getting much help
from your plan, and if you're paying for this I can't see why from this
example.
    It is not unusual for a patient not to be able to crown a tooth
immediately.  In this situation (and esp. if I know the patient can be
trusted to return) I will sometimes restore the tooth with a filling
after shortening the tooth (therefore removing the tooth from most
biting forces) as long as they know the tooth MUST be restored more
definitively within a reasonable period of time (maybe a year).  There
are few common scenarios in my office more disheartening than having a
patient go through a root canal, and next year having to extract the
tooth because it has cracked or rotted.

Steve

Depends largely on your geographic location.
In my area a RCT and Crown on a molar runs
~ $1,400 - 1,800

I rarely wait more than a month. It really depends on the tooth
in question.

Only as a temporary measure until you can afford a permanent crown.

Since it's a molar, what I would do is complete the root canal therapy
(clean, shape, and fill the canal spaces with gutta percha) and
probably restore the tooth with a cusp coverage amalgam core buildup
at the same appointment (if the tooth has been asymptomatic) or soon
thereafter (if the tooth has recent pain symptoms).  The amalgam core
buildup should easily last a year (I've seen them last a LOT longer
than that).  It's very important to complete the root canal therapy
ASAP and restore the crown of the tooth with a durable restoration
quickly so it doesn't fracture.  

On molars I recommend a fully coverage cast crown eventually.  I have
seen endodontically treated teeth with amalgam cores fracture and the
teeth required extraction but that's rare if the amalgam is done well.
Some docs restore endo treated molars with composite resin (plastic)
but unless there has been very conservative endodontic access and
there are low masticatory forces involved (such as with an unopposed
tooth) I use amalgam.

(snip)