I have the earlier model machine in the red/tan case, paid $75 for it.
I believe this machine (99K from mid 50's) only came with that one decal pattern.
I also bought the same machine in a cabinet for $100 - in about new condition. Had a pin jambed into the bobbin area and wouldn't move. Based on the condition (and that of the pin) that probably happened early in the life of the machine, and the owner just put it away as non-working and just used it as an end table (but at least not a plant stand)
I also think $150 is about $50 to high for one that needs service. However, if it was fully serviced, then I think $200 would be OK. So it's not an outragious price, just on the high end.