Budget Snake Eye Fire King

This deck doesn't include the Diabellstar package in order to keep its price below $140 side deck included, i'll explain my deckbuilding decisions as follows:

Given that the absence of the Diabellstar Engine represents a heavy hit on consistency, i've decided to use 3 Poplar (1 more than the usual) that can be used both as starters and extenders and 2 Pot of Prosperity (I think 3 would be excessive, besides you could end up drawing 2 of them turn 1).

Following this line, Snake-Eye Birch works pretty fine as a free extender in case of being ashed (the best case scenario because you could link into Hiita and then Promethean from 2 bodies), or being impermed/veiled. I think 2 Snake-Eye Birch are enough.

Zombie Vampire is there just in case you brick into Fire King, you could turn Kirin+Garunix into a Zombie Vampire hoping to mill a Snake-Eye to summon with the same effect, specially useful during mirrors. If you brick into Fire King against a skilled player, you're dead anyways, so by using Zombie Vampire you have the chance of end up on a decent board.

3 Book of Eclipse as a cheap way of boardbreaking, you could use Forbbiden Droplet instead. Both are great options in my opinion.

1 Nibiru as a Crossout Designator target, the 3 Crossouts are necessary for keeping the consistency of the deck without the recursion offered by the Diabellstar package, 2 Original Sinful Spoils instead of 1 are also a necessary evil to not brick or to be able to extend or bridge into Snake Eyes.

Bystial Magnamhut because we're entering into a more diverse format with a lot of Dark/Light monsters, also works as an extender if you're veiled, can be changed for Droll & Lock Bird as a Crossout Designator target.

Circle of Fire King and Salamangreat Sunlight Wolf as great recursion tools. Kikinagashi Fucho to stall a turn against Tenpai in case you have to go first, if you have Snake-Eye Birch on hand you can XYZ summon it easy.

Your desirable end board is: Apollousa 1600ATK (2 monster negations) + Number 38: Hope Harbinger (Spell Negation) + Amblowhale (Recursion tool and Promethean target) with Garunix and Promethean Princess on Graveyard. Number 38 also protects Apollousa from being hit by battle.

Regarding to Side Deck: Every Spell is a boardbreaker tool in case you go second, every Trap is a Win Condition in case you go first. Solemn Judgement is there to protect your field, be careful with the Fire King Island mandatory effect.