DIY is not too hard
Have you considered doing it yourself. The correct filter and pan gasket does not cost very much at dealer or here at Partsshop. I do mine on a drive up ramp. Be very carefull, chock the wheels, and use jack stands as a back up protection. You will not survive if a car falls on you.
Your manual tells type of ATF and how many qts. needed after draining the torque converter and pan. Be very clean and get everything out of the pan. Use a new pan gasket. The filter comes with a new gasket on it already. A 5 mm allen wrench is needed on many models. Use a large screwdriver to turn starter gear in the running direction until drain plug shows up on bottom. Don't tighten pan bolts very tight,and keep them uniformly tight by criss crossing in a pattern so that pan is not deformed. Don't compress your new gasket out of shape.
Upon reassembly add about 3/4 of total amount of the ATF and start engine for a one or two minute idle while selecting all gear ranges. Check level and add another 1qt if needed , check again while on level ground while idling in Park. You may have to add more ATF, get in only enough that you can barely see it on the low end of dip stick. Go for a drive 10 or more miles. Stopping frequently on level ground to check and add a little more if needed until it is correct at end of the drive (hot level is what counts). DO NOT OVERFILL-- it would be a pain trying to drain out some while out on the drive so just DON'T OVERFILL. Keep your dipstick clean. Use a slender funnel so as to have no spillage.
Its kind of dirty work but not really hard--- and saves quite a bit of $$, Best of all you sort of get to know your MB better.
87 300E, traded in but remembered fondly.