Build. Mecha Devil Horse. Plenty of attachment points on this one.
Can you build something -- a frame, station, or starship -- right away? Yes. (+5)
Is it below, at, or above the golden ratio? Below. (+5) (The Golden Ratio is $0.10 per part.)
If you can't build a frame right away, or choose not to, does it have parts you should be able to put into use right away? Yes. (+5)
Does it have more than a handful of immediately useful parts? Yes. (+5)
Score: +20 (A+). Another one for the top Mixel pile.