I know it's not something you thought you'd see in this forum

But watching ebay there are a few for sale under £30.

What's the difference between:
120S
120N
120FN
120CFN
120GFN

Like, what's with a GLASS lens in a Holga?
Does that raise the quality (hah!) to the level of a Kodak Brownie?

Why one with a flash?
Surely I can make my Canon 580EX work

Advice please ... maybe I'll try F1 photography with a Holga.
Driver portraits perhaps