I had Bilstein Heavy Dutys on my old car (1998 190e 2.3 8v) and have to say that they are by far the best shocks I ever bought. I have only ever bought Bilstein since then. I like to buy quality that way I don't have to keep changing the same parts over and over again. Shop around and you will probably be able to get them for a price that's not too far off of other lower quality brands. Here is a site with some pricing:
http://www.allshocks.com/bilstein/html/show_shocks.asp?make='MERCEDES%20BENZ'&model='190,%20190E,%20190D'&year='1988'
On the other hand, if cost is what's the most important to you right now than maybe this might help
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=7929520284&category=33590&sspagename=WDVW