what is this part? and is it replaceable? help please

[NoLimit95]

they are rusted all the way through... how much do you think it would cost me for 2 of them and the bolts needed as mine will most likely not come out to easy

If you had caught me in 2010, when I had 2 Marks in the back yard, I had 4 of those with zero rust on the braces and the nuts and bolts. I guess the Northern cars must catch hell right there in that spot. My current 95 is rust free at the braces. I know this because I use the round spot for the hydraulic jack, when I do jack it up.