This is a pretty simple Commander variant, taking inspiration from Penny Dreadful. It's meant to be played in paper.
The deckbuilding rules are like normal Commander, except each card must cost 10 cents or less. So, the whole deck should cost 10 dollars at most.
HELPER FOR FINDING LEGAL CARDS
If you're proxying a card you should use the Scryfall price, but if you get a good deal from your local game store you can use a card that Scryfall lists as costing more. (Don't lie to your friends or collude with store employees, that sucks. Also if you buy something at 10 cents and then it goes way up in price please stop using it.)
There's no banlist other than all conspiracies, so silver-bordered/acorn cards are allowed. It's a fun benefit of playing in paper! However, as a Rule 0 stipulation, I recommend checking the banned Commander cards that are less than 10 cents and discussing with your play group which ones you might or might not want to use.