I like to implement Triple Triad in my game, but I'd rather have the player buy Booster Packs each containing a random card instead of buying each card individually. How do I do that and if possible, can I implement a level system so that, for example, a level 3 booster pack contains cards from level three or lower.
Create a new item called TT Booster Pack (or something). It'll be an item you can use out of battle (like Repel), and its effect will be to give the player a random card. The item will be consumed in the process, like Repel. You can have multiple such items, each one containing a different set of cards.
A Triple Triad card is nothing more than a Pokémon species. Card number 25 is a Pikachu, for instance. To generate a list of possible cards that a booster pack can provide, use something like this:
for i in 1..PBSpecies.maxValue
cname=getConstantName(PBSpecies,i) rescue nil
next if !cname # Skip if the species doesn't exist
next if level>3 # Skip if the card doesn't match the criteria
array.push(i) # Add card to array
The above code makes a list of all cards of level 3 or lower. Of course, your criteria can be different depending on the booster pack, such as different level limits, elemental types, habitats, or be a predefined list of contents (e.g. legendaries pack). You could get quite interesting with this.
Just pick a random entry in the array and give it to the player. Simple.