$10 will provide enough cleaning potion for onelength of pipes in the chamber of secrets.

Basilisk Burial requires giant, thestral-carried shovels. We need at least 4 shovels to carry the Basilisk and bury it.

Seeing that there aren't many witches and wizards who can still speak parseltongue, we need to buy a Parseltongue Translator device from Borgin and Burkes.

We need a new chamber door and painting once the basilisk is extracted. Sir Cadogan has valiantly accepted to guard this door, for a fee of $600/year.