if you want white cards the red white event deck (forgot the name) has some good cards, thalia, silverblade, clifftop retreat. If you can find one at MSRP ($20-25) then the cards inside are really good value for the money.
In my experience, most FNMs (depending on your area) are at least moderately competitive. You'll see at least a couple top tier decks and probably some tier 2 decks that will give the top tiers something to think about. I know people in my area use FNM as a training/testing ground for their PTQ and SCG Open decks. So just tapper your expectations if you show up with a home brewed deck or a netdeck that's not finished.
also the cost can look overwhelming, but in the long run it is theoretically cheaper to buy single cards if you want to build a specific deck. opening packs will get you some things and things to trade, but will be a more significant investment, I only buy packs when I don't know what I want, or just want to scratch that itch