Can you use an ability and scrap a card in the same turn?
According to the Star Realms rules, I think your interpretation is correct: you may play a card for its trade value, then scrap it in the same turn.

The relevant text (in the third row, top):


  When a Ship is played, its Primary Abjility triggers immediately.  If
  a ship has an Ally and/or Scrap ability, you may choose to use one or
  both of these abilities any time during your Main Phase (provided you
  fulfill the obligations for doing so).


Your interpretation is supported too from the Main Phase description:


  At any time during your Main Phase, you may perform any of the following actions, in any order you wish:


And then finally, under Using Abilities:


  With the exception of a Ship's Primary Ability, players may use the various abilities of their in-play ships and Bases at any time during their Main Phase.  Each ability may be used just once each turn. (emphasis mine)


Since a ship has more than one ability (primary, scrap), each ability is only being used once per turn, too.