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.
I needed more agro options, more simple decks, and just more choices, so here we are- Gruul agro. Bloodthirst, Raid, and Bloodrush are all on display here, and all reasonable. Fun, interesting, playable.
As for budget: Maindeck cost is currently at about ~$10 (according to the middle blue numbers on this very site under estimated value), sideboard at about ~$3.80, which brings us in nicely (barely) under-budget.
So mostly this section is going to be notes on why I think these are good cards to learn from:
Just walking up the mana curve- Tattermunge Maniac is a fun card I discovered that I should probably be playing in a bunch of G/X or R/X agro decks, but I'm trying to not run hybrid mana in decks that are only one of the colors in this series. Not only does it goof up MTG Vault's representation of the deck's colors, but it's just something players can figure out on their own.
Kessig Prowler can just be a Savannah Lion and hit people in the face, and can serve as a mana sink late-game if you're flooded, and both Jackal Familiar and Rigging Runnner are meant to enter as 2/2s for R, which is pretty solid.
And, finally, Wasteland Viper isn't as hilarious as Ambush Viper, but it's much better-suited to this deck, allowing you to save your creature, kill theirs, and if none of that is working out, just play it as a 1/2 deathtouch for 1, that's a fine card.
At 2 cmc, Strangleroot geist is just good, a 2/1 haste for 2 is passable, and a 2/1 haste for 2 that comes back as a 3/2 whenever it dies is worth paying GG in a 2-color deck for.
The rest of your 2-drops rely of your 1-drops to deal some damage- They have Bloodthirst, so they should be entering as 3/3s for 2, one with menace before menace was a keyword, another with trample. Both are strong and hard to deal with, and turn the aggression you're already doing into a tangible benefit.
For other spells, I went less into removal because, well, the goal is that anything you'd remove, they already need to be blocking with, so if you can ensure that those blocks go in your favor, you'll be pushing the damage anyways. And that's why we've only got the playset of Shocks to remove, accompanied by a playset of good old-fashioned Giant Growth and it's angry, trampling Gruul Cousin Colossal Might.
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.
Goblin Diplomats is funny and lets you get their blockers out of the way, extra wasteland Vipers are for good trades, Destructive Revelry hates artifacts and enchantments, Gruul Charm is useful in a bunch of eclectic corner-cases, killing fliers, ignoring blockers, or dealing with mind control effects, on the off-chance you're worried about them. And Searing Spear gives you extra removal. Green Fight effects aren't as good with creatures as fragile as these, so I stuck with red removal for this one.
Finally, Skarrq Guildmage, which you can use in matchups where you can't quite get it done quickly to give your top-end a bunch of 4/4 land attackers, which is pretty sweet.