Travel on JetBlue is free in coach, you have to pay taxes for international. 75/leg for Mint, Buddy pass riders are not eligible to fly in Mint. Zed fare agreements with just about everyone.

We get four one-way buddy pass segments every quarter (2 round-trip equivalent), they expire after a year. I use mine occasionally for elderly friends with flexibility to travel New England to Florida, it seems to cost them about 60 dollars per person per leg for that distance. (The charges are distance-based). So useful with a bit of flexibility or last-minute, but you can do almost as well with cheap confirmed tickets if you plan ahead...

Don't have the time to type out schedule stuff right now. Hope this little bit helps, welcome to JetBlue.