I bought my Lubi back in 2003 I guess, also around € 20 + shipping, don't know exactly anymore.
It was fun to learn the basics of photography, as it has no batteries/meter you have to do everything manual.
I also liked the way of taking photos, viewing from above.
I used it for night photos, on a small tripod, or on the ground, long exposures with fuji reala 100 iso film, with cable release, in cold winter, freezing hands, ...
Nowadays I'd do this with a thermos of coffee to keep me warm.
A few nightshots I took are still available here in this album, giving you an idea of the nice atmosphere you get :
https://www.lomography.com/homes/dikkie/albums/620712-lonely-nights
(except the rectangular photo was shot with the Seagull 205-A)
Here are a few weird portraits I shot too:
https://www.lomography.com/homes/dikkie/albums/620711-portrait
Even if you're not shooting film, you can shoot photos with another camera (even digital) from above, like in this shot:
Wildlife by
Bulevardi, on Flickr
The only negative points I can think of is the limitation of 12 pics a roll... but I shot a few rolls of regular 35mm film with this too, which gives you weird large exposures on the slides, where the sprocket holes are exposed too.
I once put the instructions online on a blog I don't maintain anymore... right here:
https://theboulevardexclusive.wordpress.com/2009/09/12/how-to-get-a-35mm-film-into-a-lubitel-166b/
I think it was an outdated slide film, cross processed.
Anyways, have fun with this cool camera!