The Breton Cider is certainly widely available, and very tasty it is too. There was even 4 types available in the small shop at the campsite! Prices in the region of €1.70 to €3.50 for 75ml bottles in the supermarkets, with most around €2.60
Didn't get to the Brasserie de Bretagne brewery, but sampled their beers (six packs from supermarket and in local restaurants). Thought most of them were quite decent beers - Britt Blonde, Dremmwel Blonde, Dremmwel Dorée, Gwiniz Du and really liked both Britt and Dremmwel Rousse. Have to say the Britt Blanche was absolutely dismal though.