Investment In Rares (Prediction)

Now I know no one can calculate the exact amount an item will go up , but so far, I've invested in a Red H'ween Mask and a Santa Hat. I know rares won't be going down , and only rising. But I ask the fellow Sythe community , how much do you think santas and masks will rise until they finally stop?

 

They won't stop. Unless Jagex makes them untradeable (which will NEVER happen) they will continue to rise.