This is a bad start. If you are starting in Vancouver, you aren't going east to west - you're going west to east.

$10 bucks a day is reasonable if you don't pay for accommodations. Food isn't expensive if you buy and prepare your own food, forget about energy bars and all that nonsense buy real food in grocery stores and you'll be ok. If you want to go cheap and light, look into couscous - lots of everything you need for a day in the saddle, it's easy and fast to prepare. Experiment at home and see what you can do.
BTW I don't know where you are buying oats but around here (Toronto) oats are ~$2.30/kg.