For Jalie, I buy them from sewingpatterns.com, and only when they are having a sale on independent patterns. I also prefer to buy Kwik Sew from that site under the same conditions, but if I need something right away, I will buy them at Hancock Fabrics.
I actually e-mailed Jalie about the panty problem and they said their very early patterns had granny panties, then the revised them too far in the other direction, and apparently their new patterns are supposed to be better, but I have not tried them. It's probably best to just compare it to a pattern that you know fits so you know where you need to adust.