New-ish player, looking to spend a £5 appstore voucher on the game!

I’d get dark side pack. I use Dooku and Royal Guard all the time as they make a fantastic team once you get Nihilus. But even without him they’re useful. Talia and Snowtrooper are pretty useful at lower levels and can be useful for certain events later in the game. The starter packs are also the only thing in the game that are worth their price imo.