A good monored is actually dirt cheap to build, with Goblin Guide, Fireblast and Fetchlands compounding the expensive stuff, but being replaceable for low-powered games. I'd actually go with a lightning-fast red deck, and that means dealing 3 damage per mana spent, 2 simply won't cut it. Lightning Bolt you already have, but I'd look into finding Lava Spikes and Rift Bolts, and possibly CHain Lightnings (it was reprinted in a retail product, so it might have gotten cheaper). I'd also cut down on lands, playing 20 tops (you only need 2-3 lands to operate with such decks), and getting 1-2 Barbarian Rings in the mix. Then, for creatures, I'd go with Mogg Fanatic and Keldon Marauders, and lose the equipments (anything that "turns on" opposing creature removal - a given in most decks - is bad for the strategy). I'd top it out with Incinerates and the new incinerate from M13 (forgot its name, sorry), and consider 2-damage dealing spells only when they offer something very good (Magma Jet, and Seal of Fire is actually a possibility depending on what you play against, since it represents a low investment you don't need to "cash out" instantly), or more expensive spells that help close out in a longer game (Shrine of Burning Rage). Since it's for casual games only, I'd consider throwing in some Demonfire or any other X spell that can't be countered under some circunstances, perhaps just 1 or 2. It should still be a dirt cheap deck, though.