the fact that you ask these questions and think that a PVC suit could be a substitute, indicated to me that you really shouldn't buy these things. Really PVC is not a chemical and gastight material. If you want a decent (relatively) inexpensive suit, get a gas-tight and chemical resistant suit. Like Tychem TK or Tyvek Pro-tec F. (or something like)

First of all you have to carry these stuff with you anywhere and know when a CBRN has occurred for it to be useful. Generally people don't carry these things or don't know when a CBRN incident has occurred. Secondly when a CBRN incident has occurred, GET OUT. Don't stay, GET OUT or take shelter. You also forgot to mention decontamination, which is just as important. No suit is going to protect you when you been contaminated.

If you want to prepare for a CBRN incident, first learn about wind directions, how to recognize a CBRN occurrence and how to act when you have been contaminated. Than a few small items would help, like a N100 mask (stops most particles from dirty-bombs, smoky-bombs and biological hazards from being breathing in), soap, towel, spare clothing packed in a vapor/gas tight bag. (Tychem TK bags are available) The rest is just not practical to carry.