Told you already. G1, GH1 body only, they're still under the 'retro' radar so prices are still good for them. It won't last, though. Comparable Olympuses have already grown past 200. Even really aged epl1-3 go for 300 already. And they're really weaker cams, no viewfinder, and no dials. G1/GH1 were flagship cams in the time, and they still hold well.
Then you need cheap fast manual prime. You want nice blurry background, that's all lens. Meike, 7artisans, Yongnuo 35mm to 50mm, 25mm will be a bit too wide. Or adapts one of the classic 50mm lenses, but that includes adaptor, a tinny bit of knowhow, and gamble regarding lens quality. It used to be the cheapest option, but you missed that, so chinese manual lenses are best option for budget.
You want raw output and quality controls. When shooting you put iso to lowest possible and cam on sturdy unmovable spot, then engage timer of few seconds to remove blur.https://www.youtube.com/watch?v=FQ4UGk_2I9k&feature=emb_title