You can easily tackle breakfast and lunch, and the occasional dinner if you're so motivated, by making the rounds of the Marche (market) as it moves from Provencal town to town.  Learn the schedule beforehand and plan your trip so that you'll be in the towns you want to visit on market day: 

Tuesday through Sunday: Avignon

Monday: Bedoin

Tuesday: Vaison la Romaine

Wednesday:  Arles, St. Remy, Malaucene

Thursday: Nyons, Isle-sur-la-Sorgue

Friday: Chateauneuf-du-Pape

Saturday: Arles, Valreas

Sunday:  Isle-sur-la Sorgue (don't miss this one)

At the market, if you're assertive, you can almost eat your fill of samples without buying a thing.  Samples are plentiful for fruits and produce, cheeses, breads and pastries, olives, some meats, tapenades and other spreads.  If you're somewhat less of a freeloader, load up on these delicious, ultra-fresh items in the morning, and picnic with them for lunch.  There's no shortage of picturesque spots to throw down a blanket and open up your goodies.  Make sure to buy some bread, local dried meats, cheeses (particularly goat's milk cheese), olives, pates, tapenade, some of the local exotic fruit, and definitely, some white asparagus, which is delicious raw, doused with olive oil or tapenade.  Also, fine a seller of local jug wine, often a cooperative.  These wines are quite good, very inexpensive, and in many cases, they represent a big part of the local family farmer's income - so you're supporting the locals,

If you tire of picnicking and want to sit down with table service, choose a bar or cafe.  Salads are amazingly good, and the paninis are unlike any sandwich you've had in the states.  Next in line pricewise is a brasserie, with a restaurant usually being quite expensive and often a bit snooty if you try to order table wine or only one or two courses. 

Finally, be careful that you don't get duped when paying the bill.  Service and tax are included in each individual menu item's price, and then the bill breaks out the portion of your total bill that represents that service and tax.  It's not meant for you to pay it separately, but most Americans do it a few times before they catch on, particularly because the bill often says "subtotal", when, in fact, the amount at the bottom is in fact, the "total".   Until we figured it out, we paid the "subtotal", also paid the amount listed as service and tax and then left a tip, which means that we paid about a 50% tip.  Don't fall victim to this.