Installing a AC in the DX

I have found this new AC kit for about 400$ for my 92 DX that came without one ,what you guys think is it a good price or i can get a better price? I was looking over the internet to see if i can find some instruction on how to install it,but found nothing yet.I just need an ideea on how dificult this would be.ALL the answers are welcome.Thanks

make sure its r134a not r12 system. idk the prices of ac system but i know they can get expensive. i think that the guy at firestone told me like 700$ just for a new conpressor