This might be an opportunity for only the most dedicated PlayStation fans, but Sony will open pre-orders for the PS5 to a limited number of people - despite the fact we still don't know the price or release date of the console.
Invitations for pre-orders are being sent to some PSN users who register through the pre-order site, although those chosen are selected "based on previous interests and PlayStation activities". Those who receive an email invitation will be alerted before pre-orders begin, have a limited amount of time to place an order, and the whole process will work on a first-come-first-serve basis. You can't just buy everything, either: there are restrictions on how many items you can pre-order, with a limit of two on accessories like controllers, and only one PS5 console can be bought per PSN ID.
It's worth noting this pre-order initiative currently only ships to US addresses, so if you're based in Europe, I'm afraid you'll have to wait longer for the opportunity to place an order. Or find a reliable buddy in the US who won't steal your PS5.