I've already put my electric drill in Streetbank. People can borrow it for free. But perhaps someone might pay me to use it? So I've registered an account on Rentl, a Swedish service, and made an ad for the drill there. 50 SEK/day, is that reasonable? Too cheap?
There are 117 items for rent in Sweden at the moment. Which is not really a lot. But you can find anything from cars and houses to tents, suits and golf sets.
What I should do is to go through all my things more systematically to see what might be possible to rent/lend out. And then to post them on as many pages like this as possible.