If a 1 year old can slackline, so can you!
This slackline is a homemade variety. We used a 50’ piece of 1” tubular webbing, 2 steel rap rings, 2 steel oval biners, and 2 10’ pieces of webbing for wrapping the trees. Pretty cheap, but takes a little practice to rig it and you need a couple beefy guys to pull it tight.
Gibbon makes a simple ratchet-strap type with 3” flat tow-strap webbing that can be set up by one person.