Looking for an m4 that wont cost me a liver

im thinking about buying an m4 and idk whether my choice (specna one m4a1 the one without rails) or a modern looking m4, what i want is good and reliable performance, not speedsoft fast performance. more like bbs flying well fast enough to reach target in a good time, not rate of fire or trigger sensitivity. im an ak guy and im sick of not having avaible spare parts. budget for thee gun only goes max 180-200€ thats why i picked that specna