I hear people talking about investing in items all the time, I just think what's the point in buying something that you might use in the off chance it might rise, I agree with Trojann and usually when I buy something I will only sell it again if I absolutely need too.
Currently I just spend my points on undesirable tasks, or tasks I've gotten bored off and only sometimes do. Also it's 225 points for completing task 50 with duradel.