It's a completely manual SLR so you can use just about any standard flashgun. I think it even comes with a pc flash socket, so you can even use really old flashguns which were used when hotshoes were just plain accessory shoes and lacked any electrical contacts.
There's no point in buying a flash, you can get one for free on your local FreeCycle group. manually controlled flashes make you think a bit more as you have to relate the aperture and film speed to the distance of your subject (read the distance from the focussing ring on your lens), but there's always a calculation table printed onto the flash. Automatic exposure units just need you to set the aperture as directed on the flash and then the flash adjusts it's own output depending upon how much light gets reflected back from the subject, but they frequently make the wrong guess, so I prefer fully manual units.
Note that I haven't mentioned shutter speeds as they have no direct effect on flash exposures; all you need to do is to pick a shutter speed which ensures that both shutter curtains leave the film fully exposed at the moment of exposure. On most SLR's this will be 1/60th or slower, and if the shuuter spped dial has a speed with a letter X next to it, then that's the fastest shutter speed you can use with flash.
You need to choose the flash according to what you want it for. A small compact unit is lightweight and will still outperform any built-in flash but it might not give a wide enough coverage angle if you have a lens wider than, say, 35mm. Some flashes are designed to work at wider angles, sometimes via a clip on adapter, and others may have a zoom head which you adjust to match the focal length of your lens. There are big heavy duty hammerhead flashes and there are also small specialist ring flashes where the flash tube fits on the end of your lens to give very flat, even, shadowless lighting for close-up shots of small objects. They're a specialist item which few photographers ever need.
To help you to choose a flash you can look at it's quoted guide number (GN)
. This is usually quoted in metres but some are a bit backward and still use feet, normally because it makes the quoted number bigger and therefore makes the flash seem more powerful. The calculator chart on the flash will still normally use feet and metres though.
I hope that I've assisted you, please take a moment to rate my answer or add comments to ask for additional clarification if anything I've said has left you scratching your head.
So called "dedicated" flashes are unnecessary for your camera. They have additional electrical contacts which exchange data with the camera, but yours lacks the facilties to use them.