Exhaust and transmission fluid leaks

On my 1996 G20, the transmission fluid began to about a week and a half ago. Before I had the chance to bring it to the shop, the exhaust began to make a buzzing sound like there was a leak. I brought it to the shop, and he said I needed to replace the flex pipe. He called a parts dealer, who told him the part cost $210. This seemed rediculous to me, as I have heard these parts cost less than $100. Also, I asked him what that meant for the transmission fluid, and he didn't give a clear answer. Any thoughts are much appreciated.

Your fluid began to.... ? Leak? Stink? Change colors? you left that part out... :D Also, I dunno bout a flexpipe... as far as the flex pipe, you can use a 91-99 Sentre SE-R/200sx/nx2000 pipe instead as they all have the SR20DE engines... so maybe check out different Nissan parts sites...