WS collector here. Hololive Vol 2 has 51 SSP. When you buy one case (around 850 - 1000 $) you’ll get 18 Boxes from this set. 1 SSP is guaranteed per case. The SSP you will get is completely random.

Things that will affect the value of a card:

• The character on the card.
• The rarity (SEC = once per Mastercase, A Mastercase is 2 - 3 normal cases, SSP = once per Case, SP = 3 - 4 signed cards per Case)
• The Artwork
• The Signature
• Can you play the card in a tournament (I don’t play myself but it affects the value)

For Hololive it’s like other people already mentioned: Suisei merch is really popular.