Custom Buy Tab

So I was wondering if we could have a different tab, where you can set a custom buy hud while in game. Since I play Sona and I want to buy ancient coin , but its not on there so I need to search it, or maybe I can put the items I want on the custom buy page then once I join a game I click on the tab and I see the things I want to buy first hand. Or maybe 15 minutes in I need my Ardent, so its on my custom buy list, and I don't have enough gold. When I do it alerts that I have enough and that its on my custom buy list.