It is not possible anymore, but you can install appcake instead by going to cydia, search for appcake, then installing it
i dont think so
Installious has been illegal and has been gone for a long time. Use the alternative called Appcake. Add the repo to your sources: http:/.cydia.iphonecake.com/
Yes, many Cydia apps or packages are free. You can simply download them from Cydia. Others must be purchased. To pay for Cydia apps you will need either a PayPal or Amazon account.