The last place I designed that was actually built had a blueprinting & construction price tag of around $175,000. Cheap, yes. But it was in an existing space with a completely open floor-plan. So there wasn't any worries about fitting around structure. That was around 10 years ago... I'd imagine the same place would be around $225-250,000 currently.
It was "semi" pro for lack of a better term. There were a LOT of corners cut to fit within budget. Too many corners from the original design. But it worked out pretty well. "No frills" though... A lot of bare drywall (I wanted cedar) and whatever paint was on sale and sprayable. The cheapest possible flooring, the cheapest possible lighting (lighting is freaking important unless you want to place to look like a dungeon). Had a lot of potential if they could've stuck with the $250,000 budget from the start. But even that's cheap for a decent place.