title: Do I need a sort key or should I use AWS DAX
body: <p>I have a dilemma and I know I should of used an SQL DB from the beginning.</p>
  
  <p>I am unsure if I can use a sort key for my particular use case. I have a table that contains multiple attributes brand, model ref, reference... What I am trying to do is let the user select brand then the model then the reference etc then get all products that match that criteria and give a mean of the prices of those items.</p>
  
  <p>Now doing a scan operation of the whole DB that has 300K+ items is not very cost effect to say the least but this is the situation I am in.</p>
  
  <p>My question is how can I most cost effectively do what I want to do? </p>