I was shocked when I saw the price of OEM pads for ~$350 for just the fronts. And this is a common sentiment even some on the old Facebook have exclaimed they were going to be charged $7000 for a brake job.
The first step is to decide if a brand new rotor is for you. It is likely you could grind the existing rotors for a small charge at a local parts shop. Usually a rotor will last at least two pad changes. If you can use your existing rotors the next step is to buy pads. Porterfields are popular and discussed elsewhere but at the time I was on a budget as I was going through some life changes. I took a flyer on reasonably priced pads.
DFC 5000 Brake Pad Review for C63 and C63s
I researched some options and went with rockauto.com for DFC 5000 semi-metallic brake pads. DFC 5000 are their OEM replacement level pads, meaning they are designed to perform just like OEM. I believe DFC brakes are also marketed as a different brand as well as many auto parts are. These Pads were about $70 shipped for the front, and $60 shipped for the rears.
I ended up having a local shop, mid-shore auto imports, install them as I've used them before and I trust the work they do. However it's a fairly easy diy. Just lift one side of the car at a time as my jack does not reach to the front lift point. A reasonable charge may be $200-$400 depending on if they grind the rotors down or just put the pads on.
Dynamic Friction Company 5000 Driving Impressions on C63
These are quite pads! They require a longer braking in or bedding period than other pads I've used and in this period I was worried about the lack of initial bite. This fear was alleviated as more miles racked up and the initial bite felt very much like OEM. Perhaps the slightest less initial bite than oem. Compared with OEM these produce lower dust, but not as low as a ceramic pad. These pads are much quieter than OEM.
I'd recommend looking at the DFC 5000 If you have a C63 or C63s. At this time I can only comment on non-ceramic rotors. Check out rock auto for these parts.