Yea I was a little confused in the beginning since you need the starbits in HE to buy cards. This also applies to buying packs and cards off the market.
Since you didn't know about this, do you know about cold pizza slices and pizza boxes? The cold pizza slice gives you a full energy bar every 24 hours and pizza boxes store a discarded pizza. The best thing is you can buy them off the market using starbits in HE.