Well, hopefully I can be of some help. I also have a 93 ranger, and was looking for the r12 refridgerant. I've found some r12 recharge kits and replacement kits, that come with everything you need to recharge your r12 system. Less than 50 bucks. Yeah, for less than 50 bucks... heres a link:
http://cgi.ebay.com/ebaymotors/ws/eB...970434088&rd=1
Hopefully you have an eBay account. If not, I HIGHlY recommend it. Ebay has saved me TONS of money, and has helped me find things that are now obsolete. Anyways, hope this works for you.