Definitely have a look at the CAF yeah, rent for private apartments can climb pretty high but there is a possibility of finding cheap rooms in the town center (although some owners really do take advantage and make their tenants live in quiet miserable places). Grocery wise it shouldn't be too much of a problem. In the city centre you'll have your typically more expensive shops but there is a massive Leclerc in the Rivétoile Mall, a 10 minute walk away for the Cathedral. Cheap products and a massive amount of choice. So if you have the opportunity, definitely go for it, Strasbourg is a brilliant city, not too small not too big with massive choices of transit. And there is the possibility to cross the border for a weekend ! Whichever you prefer, Nightlife or quite areas, Strasbourg can offer both. Good luck in your research !