Even discounting Skullclamp ($1.99) and Sol Ring (which is in every Commander 2017 deck but, as the most played card in Commander, is still worth $3.27, even with a ton of reprintings), the Vampire deck is overflowing with artifact value, with Door of Destinies being the single most valuable colorless card in in Commander 2017 at just under $6, along with Well of Lost Dreams and Blade of the Bloodchief, both coming in between $3 and $4
If all are printed equally (which is generally assumed), you have a 1/120, or 0.0083% chance of opening the $50 mythic
Use sleeves and card protectors to maintain its condition
Read the text carefully and see if you can get the flavor
These are the ones that strike the right balance between abilities, mana cost, and attainability