You mean AC adapter. PSU is a desktop term. I'm not trying to nitpick. Knowing what to call it will help you find what you're looking for.

It's unlikely that anyone will be able to tell you what specs you need simply from a photo. You need to either learn the model number of the laptop or the AC adapter that it originally came with and look up the power specs or get a look at the sticker underneath the laptop to learn them. If an AC adapter matches the voltage, amperage and plug on the laptop, then it should work. It doesn't need to be the laptop's original model, from the same manufacturer or even from the same time period (unless that's a really outdated plug type). A generic or universal adapter could work (again, if it matches those 3 key factors).

If I were you, though, I would just wait and buy a laptop that comes with the correct AC adapter and hard drive. Someone is likely to simply give you a fully equipped Win95 laptop just to get rid of it, as long as you pay for shipping or go pick it up. There's not really any good reason (such as cost or availability factors) to make a project out of it unless making more work for yourself is something that you would enjoy.