Internet links . . . how do they pay?

[Snapolit1]

Just clicked on a link at Sports Collectors Weekly and it took me to Heritage Auctions, and it made me wonder:

I've always assumed that when you click through to a link, the "referring" website gets "paid" some how. Is that typically true? And how does someone get "paid", and by who? I've never run an internet business. Does a check show up one day for clicks? And do you only get paid it the person buys something. I would have to think the pay per click, if that's how it works, would be pennies, right? Do you get a check every three months for $1.24?

I realize this is probably a pretty complicated, broad area. Just amuses me that I have absolutely no clue how this all works and it's such a commonplace thing.