So this is a project I wanted to engage in- To make a set of 10+ super-budget 60-card decks that are simple, relatively easy to play, relatively easy to understand, and bring across the fundamentals of how Magic Works. We've since gone way past 10, with tons more in the works, and I've really enjoyed the challenge of trying to make these decks easy to play and understand, fun, and all under budget.
The main goal here is that you could easily build these deck for a low cost and use them as an easy introduction to how magic works, to teach a group of new players both how to play, and give them a sense of Why, a sense of what fun things they're getting into. These decks aren't gonna be particularly good, or even legal in any particular format if it stops me from including a card I think is good for the deck, but they should be fun and interesting without being too hard to get into. They should be an easily-accessible example of how fun Magic: The Gathering can be.
I knew from early on that I wanted a sea monster ramp deck- they're just freaking sweet, alright? And I've been trying to make Bounty of the Luxa work since it came out in a lot of decks, but I think it's actually pretty sweet here. I would've swooned over Quest for Ula's Temple if it were in my budget, but alas.
As for budget: Maindeck cost is currently at ~$10.40 (according to the middle blue numbers on this very site under estimated value), sideboard at about ~$2.60, which gets us actually about $2 under-budget. You might be able to play Explosive Vegetation if you really wanted to, or Stormtide Leviathan.
So mostly this section is going to be notes on why I think these are good cards to learn from:
Embodiment of Spring is your early blocker, and while not especially impressive, he's 1cmc, he blocks, and he sacs for a land, so he does everything you could reasonably ask of a 1-drop creature for this deck except kill a 2/1 in combat.
Then, you're ramping with Farseek, Rampant Growth, and Khalni Heart Expedition, the last of which is remarkable for being actually pretty solid here- Expedition works great if you're playing ramp spells and getting more lands than just your normal land drops out. Plus, if you can chain two of them together, that's huge.
Your first-priority ramping targets are Whelming Wave, to throw back your opponent's creatures (and Embodiment of Spring, but it's a 1-drop, so you don't care), and Bounty of the Luxa, to give a nice mix of ramp and card advantage.
Revolutionary Rebuff is your primary form of interaction- it can counter almost anything, and if they're keeping up 2 mana to make sure their spell resolves, then clearly they aren't putting enough pressure on you for you to be scared yet.
And, finally, the real reason you're here is the payloads- Cryptic Serpent is a card I did not expect to be half that cheap, and it's great. Throw out a bunch of ramp spells, cast him for 4 and hold up a counter spell, or make it so he barely breaks your stride with all the ramping spells you're casting, whatever you get the opportunity to do. Late-game, he's stupid cheap, and he's still a 6/5 that will casually murder anything you don't like and sticks around after Whelming Wave. This card is great here.
Your big guns, however, cost 6 and 7- Shipbreaker Kraken starts as a big, dumb 6/6, and then for another investment of 10, becomes big dumb 10/10 that hilariously Claustrophobias down up to 4 of their creatures. Scourge of Fleets, by contrast, throws your opponent's creatures back to their hand and starts beating the hell out of them as a big dumb 6/6. Sea Monsters, they're a little bit predictable, but hilariously fun.
Manabase is meant to be a touch lacking, but also super-budget. I'll be doing the same for all of them.
As for the sideboard, this IS supposed to be a sideboard they learn how to use, to make their deck perform better in the right matchups, or just in general to customize their decks within constraints.
Extra Shipbreaker is for longer and slower games, while the Sealock Monsters get out and serve as big 5/5 blockers faster than your other monsters, which can be good against agro and midrange, though you're obviously sacrificing something to put them in. Then, when you've stabilized, you pump 7 into it and start smashing face with an 8/8.
Nissa's Pilgrimage lets you either customize your ramp options, or just bring in more, while Urban Evolution is good for value, and lets you play out extra lands you draw too. Naturalize is a great sideboard answer card, and Essence scatter was my first thought for what other countermagic to bring it. It's good for answering control decks' threats, but Simic doesn't have much to deal with those once they're on-board. Thankfully Whelming Wave is here to help, but it's not a great spot. I dunno if a playset of cancel would be better or not, anyone have any suggestions?
I kinda want to try and fit in 2 copies of Plummet, but I feel like the 4 Essence Scatter slots need to be answers you can use against ANY value deck, not just ones with flying creatures.