for me i get my oil changed by someone because i need a paper trail or i feel lazy.
what i did last time was I bought the oil from BMW and went to IVO to get it done. He charged $20 to do it. but If you need paper work saying it was done he needs to get the oil for you and do the work so it brings it $120 (I'm sure that's what he told me last time)
but I've seen a lot of oil change specials from a lot of these guys rpm, bimmerex and they use authorized BMW oil and filter (but not BMW Oil and filter), I believe most of these guys use MANN filter and whatever oil.
Alternative spend $80 and get the oil and filter from the dealer and do it yourself
hope that helps.