What is the average cost of seat spring repair?

I will try to get some pics up for you tonight. I have two different seat and springs to choose from, so it will help also if you could post a pic of what you have.
The easiest way for me to explain the difference is to compare the rear cross member. On the '72 this piece had a raised center section and used two different springs, 7 of one type and the three in the center were different. On my '75 parts car that rear bar went straight across and all the springs are identical. The springs are different between the seats, so I have three different types to choose from, plus the end springs...
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