Here is a budget list containing the best, easily obtainable cards I have used and think are strong(feel free to add in any staples you already have, e.g. Maxx C): https://www.masterduelmeta.com/saved-decks/63c60c67b7539da1cb239690 *disclaimer, this list is not thoroughly tested(I was just drawing sample hands and not playing it in ranked)

Budget Decklist UR Explainations:

• Cyber Stein: Obtainable from legacy packs(please don't craft this just replace it with something else if you don't have it)
• Ash Blossom, Lightning Storm, Forbidden Droplet & Infinite Impermanence: You can get these from the bundle deals in the shop
• Raigeki & Monster Reborn: Solo mode rewards
• Cipher Blade Dragon & Cipher X Dragon: Obtainable from the rage of cipher structure deck
• Numeron Dragon & Zeus: These are the decks win conditions and it is not playable without them

To build the actual list, the most important UR's to acquire are (in order):

• Dingirsu
• Danger Bigfoot, Gizmek Orochi & Trade-In
• Harpie's Feather Duster & Lightning Storm
• Super Poly
• Golden Castle of Stromberg & Alpha the Master of Beasts
• Triple Tactics Talent
• (Number 38 and Number 90 aren't summoned often so I probably would suggest against crafting/pulling them)