I buy my frames from “castorama” I think they must be located in Belgium. They have a range of glass frames and aluminum borders (black, aluminum or light wood color) that are quite sober with good value for money. It’s not very high-end but for 45 euros the glass frame is quite suitable. I can’t stand plexi frames and I can’t afford to spend hundreds of dollars on a frame either. personally they suit me well. It’s up to you to get an idea in a store if you find one.