title_body: Will small stake pools find it hard to cover running costs?
upvoted_answer: If the stake pool does not create a single block in the epoch, it receives no rewards.
  If it is elected and is able to create at least one block, it receives the fix pool fee, which is right now minimum of 340 ADA plus the margin fee.
  Minimal hardware configuration is debatable, but you can run a pool as low as 1 EUR (about 1ADA with today prices) per epoch.