So do we want legal-in-some states items or not?
More like 3-4 hours, and low (but not zero) cost.
Obviously the range is very broad, but around my parts you can get away with archery for about ~15 EUR per person (and up). That's not very expensive. What is "low cost" also obviously depends on the person.
Riser, plunger, arrow rest, limbs, string, arrows, finger tab. That's the absolute bare minimum. You'll also probably want an arm guard unless you don't value your forearms. You can't do this for less than US$150-$200, unless you find someone basically giving away second hand equipment.
In regards to the costs, again, what's low cost for one might be different for another. My archery club allows you to show up and try it for a session (or two) before enrolling. Astronomy nights don't cost us anything or much fuel, if at all. Been to plenty of board game nights where there were no entrance cost.
To share some contrasting opinions.
https://boardgamegeek.com/boardgamecategory/1120/print-play
&
https://boardgamegeek.com/forum/974620/bgg/design-contests
BGGs site is always a bit confusing to me to navigate, but searching for "pnp" or "print and play" and a contest year will probably surface a lot of good "free" (or at least, free to print....) You can at least certainly get a bunch printed for cheaper than 1 boxed game and if you dont like half of them, no drama.
Shutup and sit down has done a few round ups of solo-print-and-plays https://inv.tux.pizza/search?q=shut+up++and+sit+down+print+a.... I'm sure there are people on here that can recommend some +1-player pnp games.
In fact, if you buy used, and resell when you're bored of the game, if can be pretty much free.
The list is fairly short (70 activities total). Once filtered it would be easier to simply display all matching activities.
Many of the "Low" cost activities have significant upfront costs. I wouldn't describe Archery as "low cost", nor describe Astronomy or a board game night as Free activities!
It was easier just to read the raw JSON than browse the site. ( The activities are https://www.whataaabout.com/activities.json and seem to be static, not based on parameters. )