I'm looking for the most economical circuit that reasonably accurate circuit for amplifying the voltage produced by a thermocouple (so it can be read by an ADC). For the sake of argument, component count and manual calibration time is not an issue. 

It's a K type thermocouple (41uV/ºC) and I'm hoping for an accuracy of around 25ºC from 100ºC to 1000ºC. 1 sample per second is plenty. The ADC is 10 bit, and there is a regulated 12v, 5v, 3.3v and ground supply.

**Could it be more economical with the above requirements to use cheap op-amps instead of a purpose made instrumentation amp?**

As I understand, the problem with cheap op-amps is their input offset voltage and drift. But am I correct in saying: 

 - Many cheap op-amps can be offset-nulled with a variable resistor?
 - and the offset drift is relatively negligible even for a thermocouple? (15uV/ºC in the LM741)

If so, the question remains what circuit could be used. **Would 3 op-amps be necessary?** or could it be done with fewer?

Last but not least, suggestions for **which op-amp** would be appreciated.

Thanks! I know I'm asking a lot here.