I doubt you will find a good used set. And if you do, how used are they? With used ones, you cant verify the history or how old they are. Ebay has them for around $200. I suggest going ahead and buying them new.
Ebay will be the best and cheapest place if you just want a basic short ram. If you look for ones made for the 95-99 Eclipse, they will be cheaper and the exact same thing as one listed for the Avenger which is higher on price for some reason. And I do know you have a V6 and one for an Eclipse will work.
What kind of fabric? If you use a fabric that stretches, It wouldnt be too difficult. And keep in mind, fabric holds dirt and IMO would not be good on your dash.
I have a pair of custom covered door panels. They are professionally covered with black vinyl not paint. They look like stock black Eclipse panels. $250 shipped or best offer.
I have a factory cd/cassette/radio removed from my 1997 Avenger with 78,xxx miles. It is still in perfect working order and in excellent condition. It is not the Infinity radio. $75 shipped or best offer.