Payments/Buying items

Is there a way to pay for items when they are NOT associated with an event? Or pay for part of the item? 2 applications: (1) Set all our inventory online for shirts/sweatshirts, etc for people to buy without it needing to be added to every event? (2) Be able to make partial payments to an event (ex. Summer/high adventure camp). I know this can be done through the accounts but then it doesn’t show up on the event page as paid. I’m a new to using Troop track and trying to set up some of our payments to go through Troop Track, your help is much appreciated - feature may be there but I just can’t find it…