I was in 4H from age 14 to 18. I started at 14 because we moved to a new town, and the old town didn't have a 4-H group.
Mine was a town group, so no one really did animals. It was all girls (many groups are both boys and girls. None of them discriminate based on gender but a boy isn't likely to join a group of 12 girls, you know?) We did some volunteer projects, sewing projects, etc. We met once a month usually. The meetings rotated through everyone's home. Some groups always meet in a specific place like a church or community center.
I loved it. I held several offices in my club, eventually becoming president and getting involved in the area council. I ended up getting a 500$ colege scholarship from 4-H.
I am a crafty person and I did lots of fair projects. Mine were mostly sewing related. Fair is usually at the end of the summer, so I was busy all summer working on fair projects.
I still hold very fond memories of 4-H (as does my mom who was in a town group when she was a teenager). 10 years ago when I was involved, the costs were very minimal- maybe 20$/year? Those were our club dues and payed for if we wanted to go on a field trip, etc. In my state (Iowa) much of the funding for 4-H came from Iowa State Extension, so costs to each kid were small. Parents had to be involved though- driving to things and helping with meetings. The other major cost is for fair projects. If you want to sew a quilt, you need 50$ worth of fabric, or whatever. Not that all projects have to cost money- you actually get judged better if you are reusing materials creatively, etc. You also get paid a little if you win a ribbon- maybe 2-4$ (So not much!).