I would venture that you cannot get a 2.1 receiver with pre outs at $150.
Some people may have ideas on used equipment.
Another thought is for the pre-out, do you plan to use the volume control or tone controls of the receiver to control the output to the separate amp? If not, one option is to find a receiver with a tape output (assuming you will not be using that for a tape deck). The receiver will allow you to select the input, but otherwise the tape out is merely passing the line level signal to the external amp.
Again, I'm not sure you can find these features on a new unit for $150, but in the used market, this is probably more common than the pre-outs.
Tell us more of what you want to do.
What speakers will you drive with the receiver, what pro amp will you use (with what speakers), and how big is the room.
These influence how much power you need from the receiver. Also some proamps allow for variations in input levels. The levels from a home audio pre-out are designed to different specifications and are not always compatible with pro gear.
Last, give us some idea where you are. Sometimes we might know of a special deal close to you.
