They won't just do an Oil change
They will do the 10K service
Oil, Filter, Cabin air filter, and the once over, MB Service Rates
That cabin air filter will cost outside a smart canter around $35.
For detail on what should be happening at that service look here
smart USA Owners Portal - 10,000 Miles/One Year
I would hate to say it, but $120 has been one of the cheapest prices I have heard so far
See here for real sticker shock
10k Service Cost?