I know, I could pay just shy of $200 US for reproductions but you still have to drill your own holes...
My original 1977 side panels are showing there age, not so much looks but the holes have become oversized to the point It's hard to secure them so the top edge tucks in the shift console and arm rest areas...
Re-glued repairs from vinal separating from edges several times over the years...
I used a 1/8" thick 4' X 2" sheet of Hardboard I bought at Lowes for about $7.00...
I used some thin plywood I had for my patterns
Now to shop for similar texter vinal fabric...
So far I have less than $20.00 and a couple hours of my time invested...
Steps I have completed so far...

 

Very nice, mine fit horribly at the edge where the e brake cover and center console cover meet. Post up pics when your finished as im very interested in a better option,

 

The hardboard material I purchased from Lowes is 3mm just shy of 1/8"
The vinal material I used is 0.85mm the original vinal is 0.85mm...
The original side panels were only wrapped at the bottom, the top fabric was cut about 3/8" longer then the top edge of the panel...
The original panel is 5.58mm in width on the wrapped areas, the materials I used is 4.65mm in width at the wrapped areas.
This is my first time doing this and I think they turned out really nice.
The drivers side fits better than the original and I may redo it in the future, I used black finish screws with a built in washer...

Right Side over the counter replacements...
It was basically a 78 panel sold as 77 panels
Fabric was left long to tuck under shift panel and armrest...

 

Using hardboard and making templates first is a smart, low-cost approach. Once you apply the new vinyl with a good adhesive and reinforce the mounting holes, the panels should hold up much better than the originals. It’s a practical solution that saves money and gives you a sturdier result.

 

Update...
My first attempt I wasn't happy with the way the left side turned out for a few reasons...
Right side fits like a glove...
Starting with the first material: I purchased the 1st yard (54" x 36") from our large local fabric store...$15.99 yard
The bolt the material came on was 27" in width, this left a crease dead center I could never make disappear evident on the top panel in the photo.
When I did the right side I aligned the crease more to the thinnest part of the panel but was still a visible crease...
I also trimmed 1/8" off the forward top portion of the panel (long yellow line). You can see where the material pinched in 2 areas, the section that gets tucked between Lower Dash Pad and Center Gauge Cluster and the Armrest & Shift Console junction...
I adjusted my pattern and had enough material to make another left panel...
I still wasn't happy, The fit on both sides are perfect but I knew the creases were still there...
There are a few mom & pop upholstery business in my area...
First business I called wasn't interested in helping me...2nd business I called said sure bring an original so they can compare with there stock...
The material they suggested, Brand Keyston Bros. and the grain was Sierra...
They also only use one type of glue, I didn't get the brand but it is formulated for vinal tops and he gave me enough to do several panels...
So my advice is find material that is on a roll, not folded and purchase a good waterproof glue...
You can see the Left Panel is wider than the right so when ripping patterns rip one side wider, both panels are 44 5/8" in length...
If you have large cables (Power/Speaker) running under the carpet behind the seats make the length of the panels 1/4" shorter...
Bottom 2 in the photo are the new panels with the Keyston Bros. Sierra grain...