I built a big outdoor garden railway for less than $100! It's made from a bunch of 1980s holiday trains, the kind that you can find at a thrift store for $5 or so. They run on AA batteries so there's no need for power or fancy wiring. The downside is I can't leave them in the yard forever, as the plastic probably isn't UV resistant, but it's sure fun while it's set up! This layout was two loops. One goes around our homemade garden pond with the inverted aquarium so the fish can watch the train. The other loop goes out into the garden and back. Getting everything to work was a bit of trial and error, so there are some fun crashes and bloopers towards the end!
Check out the POV "cab-view" tour of the entire layout here:
