Honestly, go for low cost packs, that way if you hit big it is a nice profit and you won't lose much.
But it also depends on your coin stack.
I bought all the UL packs because you get a token that can be used in a couple of sets, worst case you get set pieces and for me that's ok because I plan on doing future UL sets. If not I can QS for training and pull when there's a decent training option.
But on a budget, the low cost packs would be my suggestion