Here at Infinty there are two main shops and both are taken care of automatically through the site. You do not need to keep track of your currencies as the site does it for you :)
The card shop
is where you purchase booster packs. Each pack up for sell will show you how much it costs, how many cards there are in it and finally the theme behind the pack.
If you have enough points to buy a pack just click the buy link, if you don't you will see a message telling you that you don't have enough points.
If you wish to buy another of the same pack you can refresh, but please becarefal all sells are final there will be no refunds for accidental refreshes.
Wallscrolls are the trade shop here at Infinity, each one costs 25 trades (card count and yes member cards do count). If you wish to purcahse them you must enter your trades on the site
Once you have enough trade points you can go to the Wallscroll shop
and just click on the scroll you want to buy it. Once again all sells are final