I make my own purée all the time. I like to call it Fruit Demiglace. I take whatever fruit I want, purée it, then slowly and I mean slowly (because you don’t want to burn it), cook it down over low heat until it’s very concentrated. Depending on the fruit, sometimes I’ll adjust the flavor with a little sugar at the end in case there is bitterness. Also, if I need the purée to be less liquid, I will add in a thickener, like tapioca starch or cornstarch at the end as well.
Boiron's fruit purees are great, and very dependable when it comes to making pate de fruit especially. I can't get Boiron very easily in my location, which is why I make my own most of the time. You can get it on Amazon though.....2.2 lbs of most of the purees will set you back about $50.