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 a $15 budget, sideboard included.
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.
This is one of the more advanced decks- Not really the first decks you want people learning with, but a sweet, budget deck you can use once new players are already on their feet to really knock their socks off and get them to think about something you can do in Magic that they might not have otherwise realized. This is one of the easier advanced lessons, since the only complex thing here is Soulbond (and one flicker card, but that's mostly to interact with Soulbond in fun ways), but still not a "It's your first game ever" deck.
So I got talked into making this one- I've been hesitant to do much with Soulbond, just 'cause it's one of those mechanics you read three times and then still use it wrong, but I got talked into making a deck actively dedicated to Soulbond, so it could be an individual lesson on how this kinda-wonky mechanic works. It's not Banding, at least.
This deck seems fine. I could've also gone Gruul with it for first strike, or Selesnya for Double Strike if I really wanted it to pack a punch, but I like Simic for Card advantage, Turn to Frog, and one flicker effect for shenanigans.
As for budget: Maindeck cost is currently at a little less than ~$9.60 (according to the middle blue numbers on this very site under estimated value), because most soulbond cards are dirt-cheap, sideboard at about ~$2.69, so we're way under-budget on this one.
So mostly this section is going to be notes on why I think these are good cards to learn from:
So let's start with the Soulbond creatures, I guess- Wingcrafter is sweet with your stat boosters, because that's a lot of flying stats coming at them, Nightshade Peddler can turn your weaker creatures into some nice trades, Tandem Lookout is good for card advantage, and Druid's Familiar and Wolfir Silverheart are just sick beats.
Synergizing with these- Coiling Oracle cantrips itself and can trade off thanks to Nightshade Peddler, or can actually deliver some fine beats with a Druid's Familiar or Silverheart. Or poke in flying if you don't have a better one yet. Flowering Lumberknot is a fantastic Soulbond target that just gives great stats for the deck, but is super-reliant on a Soulbond Creature to be useful.
For spells- Pounce is great with all of these big green bodies- Lumberknot can Pounce even if it's not Soulbound- Turn to Frog is a great way to wreck attackers and blockers, Illumination lets you draw cards or cycle if you can't afford it, and Ghostly Flicker is a nice way to adjust your Soulbonds if you need it, and unless I'm mistaken, you could do that midcombat to give your creature Tandem Lookout's Ophidian effect after blockers are declared, or buff some stats to eat something. That seems like 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.
Uninvited Geist seemed like a fun way to push damage in this deck, since a 3/3 unblockable becomes real nasty, Essence Scatter gives you another option for dealing with enemy creatures, Jace's Ingenuity is for boarding in against slower decks, Naturalize and Plummet are classic Green sideboard answers, and Sheltering Word is a great way to protect your units and gain some life. Could be replaces with Ranger's Guile if you wanted to, but I always try to have a little lifegain in the sideboards, and Sheltering Word on a Wolfir Silverheart is just back-breaking.