Most independent shops are running on thin enough margins that they probably can't afford to offer 'CCA member discounts on parts & service. They typically have less overhead, so are able to charge less than dealer rates. Can't speak for your area, depends on the dealer, but, around here, dealers have a 10% parts discount for club members, I don't think they have any discount on labor rates. No idea on what oc/f (oil change & filter) & plugs for your car, but you can price shop parts to get an idea. Lookup part numbers on realoem.com for your car (month & yr. production date on your door sticker), and then you can google part numbers (it helps to add 'BMW' to the search with the part #) &/or check prices from Roundel advertisers, and you'll start to get an idea of the parts. If you're not sure on what all might be needed parts-wise, see the bavauto.com blog posts or youtube vids, or other youtube vids. For instance, you'd expect most oil filters to come with a crush washer for the oil pan drain plug, but if they don't you'll need one (even though it's less than a dollar). If your chapter website has message forums or social media like a facebook page, you may want to put your question there to see if others in your area have suggestions.
My independent charges 05 hours for oil change, $45, $45.50 for 6.5 quarts oil, $14 for filter. 1.5 hours for Plugs, $135, $15 for 6 plugs.