Pack offers

 Economy wise- the 2000 crystal pack will give you a LOT of new heroes, and this will give you hero quests, which leads to a LOT of new cards and gems. Saving for 5000 is not only hard, but it it is actually slower since you can't do all those hero quests. The hero quests will allow you to reach your second 2000 multipack a LOT faster, and give you even more hero-specific packs from these quests. Therefore the 2000 pack is very economical for free to play players. If you are spending a few bucks, then the 5000 is a better deal.

Rose is one of the most rare card dependent heroes (in my opinion). You definitely need the briar rose, three headed chomper, and cornucopia to sorta optimize the flower theme deck, which is what her combination is most suited for. (theory crafting on paper mostly).

The cheap version of rose will involve a lot of FREEZE, or playing beans, but imo green shadow simply does both better because she has more card draw options to allow her to dig for the freeze combo cards. Green shadow's draw card also great with beanstalks and navy beans, and bean counter, also she has access to blackeyed bean (my favorite plant card).