I'm new to mtg too and i'm trying to build a budget mono red aggro deck as well =)I'd suggest to take out bloodfray giant, chaos imps, molten primordial and rubblebelt raiders. They are too mana expensive for an aggro deck. Take out Goblin Arsonist if possible as well, it doesn't provide enough threat in my opinion. try to put in 4x (rakdos cackler, legion loyalist) for 1 drop mana and 4x ash zealot for 2 drops. Also, you have too many sorcery spells. In your main phase, you should be willing to cast as many creatures as possible to continue the threat to your opponent. so you should cut a few spells here such as flames of the firebrand. I'd put act of treason instead if you want to stick with this number of sorcery. For the instant, put 4x mizzium mortars to replace increasing vengeance and skullcrack.Also, add 2 madcap skills into it and cut the mountains into 19 - 20