You still have the option to use commands :

./use weaponname amount

./use itemname 

./store weaponname amount

./drop weaponname amount (need to be stored)

Current Items: 

Food: Boosts the player's health by 10 if he's low. 

Repairkit: Gives the vehicle 100 health (only if it's too damaged) 

Exported functions which you can use them in other scripts : (server side)
getPlayerItem(player,itemname) 

updatePlayerItems(player,itemname,value) 

TakePlayeritem(player,itemname,value)
Forums: https://forum.mtasa.com/topic/124763-relinventory-system/