Replying to How to Successfully Purchase Items in Online Limited Releases?

I've seen a lot of posts about this sort of thing on here.

I am trying to get some of the girls clothes from the upcoming H&M x Balmain release. I will be using just a regular laptop and average internet.

Do I even have a chance? How long do these things actually take to sell out? Is it instantaneous?

What are the odds of someone getting more than one item, and what is the best way to try to do this? Order one item and check out, order next item and check out? Or put multiple items in the same cart?

Which items typically sell out first, cheap or expensive? If I want a $50 t shirt and $300 pants which one should I go for?

Any other tips?

Thanks