Where is the OP from? Rust belt? Rocketman
I helped a guy do his subframe a little over a year ago and the rest of the car was in pretty good condition. The recycle yard gave him the first one and it too was pretty bad. He finally was sent a good one and we put it in. I don’t remember the make and model…I was just the helper, but I remember him saying that the recycler said that this model was prone to subframe rot.
Some are just poor design or poor quality.
Yosemite
Thanks again guys for all the responses and advice!
@rocketman : I’m from Michigan.
Also, I got in touch with someone from a salvage yard place, and they were selling a “lower front K-frame” complete with all the steering & suspension parts still attached to it for $150. It’s supposedly in nice shape from what I was told. My brother (who’s a mechanic) told me that it’s a great deal, so I’ll try to go there maybe next Monday with my brother and inspect it to make sure it’s in good shape.
Your subframe is not the only issue with this car. Has your brother the mechanic looked at the areas where the subframe bolts to the underside of the car? I’d be very surprised if that area were not very rusty too. Be sure and have a good look there before you put out good money for a part you don’t need.
The 150 is a good price for the complete assembly but the lingering unknown is whether you will be installing a used part in good condition onto a car that is rusted from one end to the other.
You state you’re from MIchigan. That qualifies as Iron Oxide country.
A local tow yard here had a nice looking 1970 Roadrunner in Vitamin C Orange for 1500 bucks.
It looked great from the road. Up close the entire rusted undercarriage could be seen along with rotted out quarter panels and Michigan license plates. Very sad to see… 
It eventually sold and the price was actually very fair considering the Mopar heritage. It’s going to take a rotisserie restoration to make it right though.
True… Thats what the Easternet is for… Buy from CA or AZ and u will receive a like new steel component.
The problem is fixed now. The original issue was that the subframe rusted out completely right at one of the 2 mounting points/bolts for the steering rack, so the steering rack was being held in by one bolt. So the rack had some play to it. This caused noise when I was trying to steer the car. The actual subframe didn’t seem too bad except at that one mounting point. From what I’ve read from another person who encountered this problem, it appears that the AC drain, drains right at one of those mounting points, and this is why it typically rusts right at one of those mounting points for the steering rack.
Anyway, so the problem is fixed now. I purchased a used, good condition subframe at a local salvage yard place for $150 and had it installed for $300 at a shop that one of my mechanic friend recommended. Everything’s working good and smooth now.
Thanks everyone for all your advice and comments! 
Congratulations!