I do'nt know if i should start here, or if i am in the right place, but since it involves a NW(DL) flight, I thought I'd ask here.

I am trying to price out a fare ex. MSP-IST via ORD with NW/TK

Pricing this seperately NW MSP-ORD r/t is $194.20 and then TK ORD-IST r/t is $649.15, however when I try to do multi-city pricing on expedia or the likes, trying to combine these flights, these options arent there, the only options then showing are UA/TK or AA/TK or NW/KL and the cheapest price is then $1007.40 or something.

The two individual tickets price out to $843.35, which is much more reasonable to me. I want to try to get these on one PNR, anybody know how?

I am just curious that if I hold a NW MSP-ORD and then a TK ORD-IST ticket, when i try to check my bags at MSP interline to IST via ORD, I dont want to end up with NW trying to charge me for baggage, since i'f flying international.

I wonder if i try to hold a NW res on their site and then go back and call nw and see if they can add a TK section to the res, but i Doubt it is possible. Anybody know how to go about this?

Since the airlines are not partners and do not have any codeshare relationship, the only way you may get it combined is through a travel agent. You'd still be subject to DL/NW's baggage fees on the domestic portion.

If you want to to make it simpler, fly UA, US, or CO (after 10/25) as they are partners.

Are you sure about that? Back in March, I flew on NW to ORD then connected to LH to fly to Germany, didnt have to pay the baggage fees.

As Andy said.

Try booking on United.com using a UAL flight connecting with the TK flight. Use UA from MSP to ORD, and TK for the IST leg.

Or pay a few bucks and book through a travel agent.

To add: I don't know how much your time is worth.But for complicated international itineraries (as this is since it essentially involves two seperate trips), I find a travel agent to be well worth the money versus spending time trying to coax online websites to give you what you want.

Sometimes Orbitz will work for situations like this; the "narrow the search to my preferred airlines" option lets you specify up to 3 airlines (or an alliance).

In this case (using 4 Nov to 11 Nov as arbitrary dates, since the OP didn't specify) Orbitz is not showing mixed NW/TK options, but NW flights routed MSP-ORD-AMS-IST with KL metal for the last two segments are pricing at $772 all in. If this fare is available on your dates, it's not only cheaper, but avoids the hassle of changing airlines and worrying about baggage fees.

my dates are March 5th outbound, March 14th return

Have you looked at the fare rules? While unusual, some fares do not allow "end-on-end" ticketing (or restrict the airlines/stock on which they allow it), which would mean the fare would not be available to combine on the same ticket as you are attempting here.