For that price, you're probably getting one of those suction cup mounts that will keep losing grip every couple of hours. If you want a bit more quality you can go all out and spend $7 on an Arkon mount (https://www.amazon.com/gp/B000U0S304). I've had the one on the link for a while and it's a world of difference vs. the durability of the cheap ones. I would just look for an Arkon one that has the threaded mount like the one you need.
Just an update, got my suction cups today.
It is not bad at all..
the contact flap material is very soft transparent plastic..top is alloy..
I just hook up to my window with a small weight and test..see how long it will stay..