I’ve never really ran a Gruul deck before so this is kind of an experiment. So thank you for the recommendations!
Gruul is fine, because you can handle almost every Threat that enters the Battlefield. For Instants and Sorceries there are some cards that at least help you with this problem (e.g.
Dosan the Falling Leaf).
The deck already seems good compared to the budget. with a little tuning like suggested it should work fine.
About the number of lands: I usually play with 34-36 Lands. In addition to this 5-12 additonal cards for mana ramp/fixing. The exact amount always depends on the average CMC and the number of colors. 3.2 isn't super fast, but since your'e playing green, this shouldn't be a big deal.
Btw, another thing that really helps me building is ordering the cards by function. lands, ramp/fixing, removal, card draw etc. This already helped me sometimes eliminating some weak spots ("Hmm.. only 3 cards for card draw. that could result in empty hands."). If you want to see examples, feel free to take a look at my decks.