You can! Their main model is subscriptions but there are ways around this. Firstly you can just cancel your subscription. So in theory you could sign up, get your crate and cancel your subscription. As long as you do this before the renewal date you should only get billed for the first crate.  Secondly, the better option is to go to the shop tab. Here you can choose from a range of one-off special crates or build your own.